Double header menu

I logged into my site yesterday, and saw that our header menu is now doubled... (see ref pic) I have no idea why/how this has happened. I have spoken to customer support and they have said I need to disable custom scripts. Can anyone shed light on this for me please? At the same time, we had a custom font for our H1's - that's disappeared too...

Is there any way of finding out which custom script is causing the issue without removing it all?

Can you share your website URL?

of course - https://www.yokecreativeagency.com/

Thankyou

Do you have anything in the Header Code Injection? If so can you post it here?

Yes - here's what's there; 

<!-- Split Section CSS from Will-Myers.com -->
<link type="text/css" rel="stylesheet" href="https://cdn.jsdelivr.net/gh/willmyethewebsiteguy/splitSections@3/styles.min.css" id="wm-split-css">

<!-- Scrolling Website Images from Will-Myers.com -->
<link rel="stylesheet" id="website-mockup-css" href="https://cdn.jsdelivr.net/gh/willmyethewebsiteguy/websiteMockupDisplay@1/styles.min.css">

<link id="wm-video-element-css" rel="stylesheet" type="text/css" href="https://cdn.jsdelivr.net/gh/willmyethewebsiteguy/VideoElement@1/styles.min.css">
<script type="text/javascript" src="https://cdn.weglot.com/weglot.min.js"></script>
<script>
    Weglot.initialize({
        api_key: 'wg_a1bc31cedb26f2d2a05609ff8395edfd6'
    });
</script>

I can't see any issues there, but I would still suggest removing it, refreshing the page and then replacing it only if the error in the header is still there.

Ok, thanks. I've just tried this, but it still looks the same. Is it only custom code in the header that could cause this? Would custom CSS cause this issue? It just seems funny that it's happened at exactly the same time our custom fonts disappeared. Last time this happened it was when Squarespace had an update. 

Is there anything else I could try? 

If you could share any code that you have added to the website that might help identify why this is happening.

Sure - 

// Website custom fonts H1&H2 //
@font-face {font-family: Gelica_Bold; src:url(https://static1.squarespace.com/static/642dcb2550586d096be3684b/t/642ecd469dfb5b75abb71505/1680788806415/Gelica-Bold.woff)}

h1 {font-family:'Gelica_Bold'!important;
letter-spacing: 0.01em;}

h2 {font-family:'Gelica_Bold'!important;
letter-spacing: 0.01em;}

// Blog Page Post Title //
.blog-title {
  font-family: Gelica_Bold !important;
}

// Blog Post Entry Titles //
 .blog-item-title h1.entry-title {
  font-family: Gelica_Bold !important;
}

// Site Title //
.header-title-text a {
  font-family: Gelica_Bold !important;
}

// Cookie Icon For Cookie Banner (Light Theme) - Ghost //

.sqs-cookie-banner-v2:before {
  width: 40px;
  height: 40px;
  margin: 10px 0px 10px 8px;
  background: url(https://static1.squarespace.com/static/5ba5e044b10f25cb908c506f/t/643244ea2c60610ca8607748/1681016042453/cookie_dark.png) center center no-repeat;
  background-size: contain;
  display: inline-block;
  content: "";
}

/*
===================================
    SPLIT NAVIGATION STYLING
===================================
*/
@splitAfterItem: 2;
@actionSize: 350px; 
@logoSpacing: 2vw;

//Width at which nav will stack
@media screen and (min-width:1200px) {
  
//Dynamic Nav font size
#header .header-nav-item {
  font-size: clamp(8px,calc(~".6vw + 5px"),18px);
}

//Split Structure
#header .header-layout-branding-center-nav-center .header-display-desktop .header-title-nav-wrapper {
  display: grid;
grid-template-columns:1fr auto 1fr;
  .header-nav,.header-title {
    grid-row-start: 1;
  }
  .header-nav { margin-top: 0; }
  .header-nav-item a {
    opacity: 0;
    transform: none!important;
    transition: opacity .3s linear;
  }
  &.has-nav .header-nav-item a{opacity:1!important;}
.header-title{grid-column-start:2;}
@splitOne: @splitAfterItem + 1;
.header-nav:first-child .header-nav-list > div:nth-child(n +@{splitOne}) {display: none;}
.header-nav:not(:first-child) .header-nav-list > div:nth-child(-n +@{splitAfterItem}){display:none;}
//Left side nav
.header-nav:first-child {
  display: block;
  text-align: right;
  margin-right: @logoSpacing;
  .header-nav-list {
    justify-content: flex-end;
  }
}
//Right side nav
.header-nav:not(:first-child) {
  text-align: left;
  margin-left: @logoSpacing;
.header-nav-list{justify-content:flex-start;}
}}}
//Give nav more width
#header .header-layout-branding-center-nav-center .header-display-desktop {
  .header-title-nav-wrapper {
    flex: 0 0 calc(~"100% - @{actionSize} * 2");
  } 
.header-actions{
  width:@actionSize;
  flex: 0 1 @actionSize;
  max-width: @actionSize;
  }
  //hide left side nav when stacked
.header-nav:first-child {
  display: none;
}
}
/*
===================================
    end SPLIT NAVIGATION STYLING
===================================
*/

#block-yui_3_17_2_1_1684143065515_3196{
--wm-plugin:websiteMockup;
}
/**
 * Scrolling Website Images
 * From Will-Myers
 */
.wm-website-mockup-block {
  --scroll-speed: 16s;
  --border-color: black;
  --border-thickness: 2px;
  --shadow: var(--medium);

  --mobile-arrow-thickness: 2px;
  --mobile-arrow-size: 10px;
  --mobile-arrow-color: white;
  --mobile-bkg-color: #ffffff;
  --mobile-bkg-opacity: 0.25;
  --scrollbar-width: 2px;
  --scrollbar-color: #333;
  --scrollbar-track: #ccc;

  --aspect-ratio: 16 / 9;
  --tablet-aspect-ratio: 3 / 4;
  --mobile-aspect-ratio: 3 / 4;

  --hover-scale: 2;
  --hover-speed: 0.8s;
  --hover-shadow: var(--medium);
}
/* ---- END ---- */

#block-yui_3_17_2_1_1684144367870_13797{
--wm-plugin:websiteMockup;
}
/**
 * Scrolling Website Images
 * From Will-Myers
 */
.wm-website-mockup-block {
  --scroll-speed: 16s;
  --border-color: black;
  --border-thickness: 2px;
  --shadow: var(--medium);

  --mobile-arrow-thickness: 2px;
  --mobile-arrow-size: 10px;
  --mobile-arrow-color: white;
  --mobile-bkg-color: #ffffff;
  --mobile-bkg-opacity: 0.25;
  --scrollbar-width: 2px;
  --scrollbar-color: #333;
  --scrollbar-track: #ccc;

  --aspect-ratio: 16 / 9;
  --tablet-aspect-ratio: 3 / 4;
  --mobile-aspect-ratio: 3 / 4;

  --hover-scale: 2;
  --hover-speed: 0.8s;
  --hover-shadow: var(--medium);
}
/* ---- END ---- */

#block-yui_3_17_2_1_1684145403876_4148{
--wm-plugin:websiteMockup;
}
/**
 * Scrolling Website Images
 * From Will-Myers
 */
.wm-website-mockup-block {
  --scroll-speed: 16s;
  --border-color: black;
  --border-thickness: 2px;
  --shadow: var(--medium);

  --mobile-arrow-thickness: 2px;
  --mobile-arrow-size: 10px;
  --mobile-arrow-color: white;
  --mobile-bkg-color: #ffffff;
  --mobile-bkg-opacity: 0.25;
  --scrollbar-width: 2px;
  --scrollbar-color: #333;
  --scrollbar-track: #ccc;

  --aspect-ratio: 16 / 9;
  --tablet-aspect-ratio: 3 / 4;
  --mobile-aspect-ratio: 3 / 4;

  --hover-scale: 2;
  --hover-speed: 0.8s;
  --hover-shadow: var(--medium);
}
/* ---- END ---- */

#block-yui_3_17_2_1_1684145625438_3579{
--wm-plugin:websiteMockup;
}
/**
 * Scrolling Website Images
 * From Will-Myers
 */
.wm-website-mockup-block {
  --scroll-speed: 16s;
  --border-color: black;
  --border-thickness: 2px;
  --shadow: var(--medium);

  --mobile-arrow-thickness: 2px;
  --mobile-arrow-size: 10px;
  --mobile-arrow-color: white;
  --mobile-bkg-color: #ffffff;
  --mobile-bkg-opacity: 0.25;
  --scrollbar-width: 2px;
  --scrollbar-color: #333;
  --scrollbar-track: #ccc;

  --aspect-ratio: 16 / 9;
  --tablet-aspect-ratio: 3 / 4;
  --mobile-aspect-ratio: 3 / 4;

  --hover-scale: 2;
  --hover-speed: 0.8s;
  --hover-shadow: var(--medium);
}
/* ---- END ---- */

/* Vertical Line */
.vertical-line {
  height: 100px; /* line height */
  width: 1px; /* line width */
  background: #fafafa; /*line colour*/
  margin-right: auto;
  margin-left: auto;
}

#block-yui_3_17_2_1_1684502781192_7018
{
--wm-plugin:websiteMockup;
}
/**
 * Scrolling Website Images
 * From Will-Myers
 */
.wm-website-mockup-block {
  --scroll-speed: 16s;
  --border-color: black;
  --border-thickness: 2px;
  --shadow: var(--medium);

  --mobile-arrow-thickness: 2px;
  --mobile-arrow-size: 10px;
  --mobile-arrow-color: white;
  --mobile-bkg-color: #ffffff;
  --mobile-bkg-opacity: 0.25;
  --scrollbar-width: 2px;
  --scrollbar-color: #333;
  --scrollbar-track: #ccc;

  --aspect-ratio: 16 / 9;
  --tablet-aspect-ratio: 3 / 4;
  --mobile-aspect-ratio: 3 / 4;

  --hover-scale: 2;
  --hover-speed: 0.8s;
  --hover-shadow: var(--medium);
}
/* ---- END ---- */

a.grid-item[href="/work/videography-brand-identity-development-website-design-gerallt-evans-metalcraft"] h3:after {
    content: "Gerallt Evans Metalcraft";
    display: block;
    font-size: 26px;
}
a.grid-item[href="/work/explainer-video-website-design-motion-graphics-greendocs"] h3:after {
    content: "greendocs";
    display: block;
    font-size: 26px;
}
a.grid-item[href="/work/re-brand-video-marketing-estate-agent-tlc-property-wales"] h3:after {
    content: "TLC Property";
    display: block;
    font-size: 26px;
}
a.grid-item[href="/work/website-design-case-study-oakwill-flooring-north-wales"] h3:after {
    content: "Oakwill Flooring";
    display: block;
    font-size: 26px;
}
a.grid-item[href="/work/animated-ident-app-qcast-london-motion-graphics"] h3:after {
    content: "QCast";
    display: block;
    font-size: 26px;
}
a.grid-item[href="/work/logo-design-brand-develoment-video-marketing-wales"] h3:after {
    content: "Margarita Margherita";
    display: block;
    font-size: 26px;
}
a.grid-item[href="/work/animated-logo-instagram-influencer-baby-led-eating"] h3:after {
    content: "Baby Led Eating";
    display: block;
    font-size: 26px;
}
a.grid-item[href="/work/website-design-photographyvideography-pdq-northamptonshire"] h3:after {
    content: "PDQ Contract Flooring";
    display: block;
    font-size: 26px;
}
a.grid-item[href="/work/animated-ident-sound-design-for-nft-platform-verse"] h3:after {
    content: "Verse";
    display: block;
    font-size: 26px;
}
a.grid-item[href="/work/videography-composing-soundtrack-mission-southstack-wales"] h3:after {
    content: "Oakwill Flooring";
    display: block;
    font-size: 26px;
}

h1 a, h2 a, h3 a, h4 a {
text-decoration: none !important;
}
 
p a {
text-decoration: none !important;
}

HOSTED FILES
mir ldn
https://static1.squarespace.com/static/642dcb2550586d096be3684b/t/655753f7ce21532e0aa3a05d/1700221943173/MIR+LDN_Email+sig+logo.png

Yoke graphics for email sig
https://static1.squarespace.com/static/642dcb2550586d096be3684b/t/6557568baedd1e6e5146e7be/1700222603821/MI+LDN+Logo-email+sig2.png

https://static1.squarespace.com/static/642dcb2550586d096be3684b/t/6557bd6245f1f157cdc10550/1700248932026/Bouncing-Y_B%26W-v2_small.gif

https://static1.squarespace.com/static/642dcb2550586d096be3684b/t/6557c44b84de84475a743c42/1700250699322/Yoke_Instagram+icon.png

https://static1.squarespace.com/static/642dcb2550586d096be3684b/t/6557c44be135f1525105d4c1/1700250699311/Yoke_Youtube+icon.png

https://static1.squarespace.com/static/642dcb2550586d096be3684b/t/6557c44b5b8dcd3d42653ac0/1700250699350/Yoke_Linkedin+icon.png

The code above is in custom CSS. 

This is in the footer: 

<!-- Split Section Javascript from Will-Myers.com -->
<script src="https://code.jquery.com/jquery-3.5.1.js"></script>
<script src="https://cdn.jsdelivr.net/gh/willmyethewebsiteguy/splitSections@3/javascript.min.js"></script>

<!-- Split Nav Code schwartz-edmisten.com -->
<script>
document.addEventListener("DOMContentLoaded", function() {
const headerTitleNavWrapper = document.querySelector(".header-layout-branding-center-nav-center .header-title-nav-wrapper");const headerNav = document.querySelector(".header-layout-branding-center-nav-center .header-nav");const clonedHeaderNav = headerNav.cloneNode(true); headerTitleNavWrapper.prepend(clonedHeaderNav);setTimeout(function(){ headerTitleNavWrapper.classList.add('has-nav'); }, 200);
});
</script>
<!-- end Split Nav Code schwartz-edmisten.com -->

<!-- Scrolling Website Images from Will-Myers.com -->
<script src="https://cdn.jsdelivr.net/gh/willmyethewebsiteguy/websiteMockupDisplay@1/javascript.min.js"></script>

<script src="https://cdn.jsdelivr.net/gh/willmyethewebsiteguy/VideoElement@1/javascript.min.js"></script>

1 hour ago, Madz07 said:

<!-- Split Nav Code schwartz-edmisten.com -->

1 hour ago, Madz07 said:

/*
===================================
    SPLIT NAVIGATION STYLING
===================================
*/

You have code in both the Footer and CSS for a split navigation, but that doesn't appear to be working correctly. After backing this code up in a note, I would suggest removing all of the split nav code, and see how that affects the design.