Image + font size change on mobile scroll

Site URL: https://magnolia-flower-z3ss.squarespace.com/about

Password Foundation

I'm getting a weird thing where the image and text jumps to a few pixels bigger as you start to scroll on mobile (video attached). 

I just want it to look smooth and stay the same size as on load. 

Try adding to Design > Custom CSS

/* About page */
@media screen and (max-width:767px) {
[data-section-id="5ffd40ddf27d2765b8cd2d32"] {
    padding-top: 100.984px !important;
}
}

Hi Tuan! You are amazing.

I've followed so much of your advice and owe almost all of my website's css to you. I am experiencing the same issue as the original poster here. I've used your suggested addition (and changed the data section ID to reflect my own page), but am still experiencing the issue with the first header block's background growing in size as you scroll on mobile. Do you have any suggestions? I've prevented the heading from growing in size with this snippet of yours:

/* Pricing Heading */
@media screen and (max-width:767px) {div#block-05499f143cfdad7f5377 h1 {font-size: 42px !important;}}

 The page is: https://voltaclimbing.com/pricing (password: 12345)

This is the CSS I'm using to target the header BG growing:

/* Pricing Heading BG */
@media screen and (max-width:767px) {[data-section-id="614b7907c73c910a2ae155fd"] {padding-top: 100.984px !important;
}}