On my dashboard page, within my Recently Watched section, regularly the buttons that should be highlighted and selecting would remove the entry from my list instead show as unhighlighted and instead would add the entry to my history again. I keep having to go into the actual history page to remove past entries, since they seem to load more reliably on that page (but not always).
Removing an entry sometimes also clears the button state for all entries on the page, which only sometimes fixes itself after the “Caching your data” bar disappears - sometimes it just stays broken and I have to refresh the page, which usually fixes it (but not always - sometimes many refreshes are required). I’ve seen this over many browsers, mostly I’m using Safari (macOS) or Edge (Windows).
Here’s what my Recently Watched section shows today (all of these are marked as watched, button has failed to set itself correctly, suggests adding it instead of removing it):
