Gallery pages - Always 4 or 2 across dependant on device

Hello, could someone clever help me with a change to my site's gallerys?

They have always worked with the below code to force either gallery as 2 mobile/4 desktop items.

Now I'm finding they can trip to 3 dependant on window size.

Has something changed?

Thanks for any help in advance.

Karen

/*Grid Galleries*/
/*Set galleries 2 columns on small tablets & mobile*/
@media screen and (max-width:767px) {
  /*Home page*/ #collection-5f0838d6114117107d0633a7,
  /*Portfolio page*/ #collection-5f0dc75be4b78a3c97a770d6,
  /*Commissions page*/ #collection-5f084534dd6f773fb0a43fb9
  {
    .gallery-grid--layout-grid .gallery-grid-wrapper {
      grid-template-columns: repeat(2,auto) !important;
    }
  }
}
@media screen and (min-width:768px) {
  /*Home page*/ #collection-5f0838d6114117107d0633a7,
  /*Portfolio page*/ #collection-5f0dc75be4b78a3c97a770d6,
  /*Comissions page*/ #collection-5f084534dd6f773fb0a43fb9
  {
    .gallery-grid--layout-grid .gallery-grid-wrapper {
      grid-template-columns: repeat(4,auto) !important;
    }
  }
}

@Karen_Ruby Hi! Can you share your site URL for context? 

Hi Sam,

Apologies I thought the URL was included: https://www.karenyeomans.com/

I want the gallerys to be restricted to either 2 or 4 only