I can see that you are using the custom method, which means it is your theme or page builder that creates the content. With reference to this documentation page:

https://searchandfilter.com/documentation/search-results/custom/

Which of the three methods are you using, or are you using the filter_next_query action in a shortcode (another alternative ‘Custom’ method)?

I suspect that whatever is making the content, is using something like the Masonry script and that needs to be refreshed on Ajax loading, but that can be complex unless the theme or plugin author is able to help. Essentially it requires javascript like this:

<script>(function ( $ ) {
  "use strict";
  $(document).on("sf:ajaxfinish", ".searchandfilter", function(){
    console.log("ajax complete");

// call your function(s) here

  });
}(jQuery));</script>

Examining the HTML for those images, the image being loaded is a transparent 1x1px laxyload image.

Do you have a lazyload setting ON somewhere?