Hello,

I have seen your video as you said that pages which you assigned in the theme settings automatically get unassigned. This may be some of your third party plugin issue which reset the theme options to default.

I also test your site by assigning the wishlist, compare and 404 page and then refresh the theme settings page multiple times and the settings not changed, the pages did not get unassigned. Also clear your site and browser cache as well that might be a cache issue.

Also i noticed that you have CDN(Cloudfare) try to check your site after flushing your server CDN cache as well.

Screenshot: https://jmp.sh/nBYXwpV

Best Regards