One of your enabled filters contains a 'bad' filtering rule. Go to Menu → Settings → Content Blocking → Filters and disable all filters to see if that will fix the problem. If it does, start re-enabling them one by one, checking after each filter if the website(s) are displayed as they should. This will help pinpoint the problematic filter.
If it's one of AdGuard filters, let us know about it by contacting email@example.com
, and we will fix the problem.
You have created a custom filtering rule that messes with the website. Go to Menu → Settings → Content Blocking → User rules and disable all active rules to see if that will fix the problem. If it does, start re-enabling them back one by one until you find the problematic rule.