Would you mind exporting your filters and either sending them to me in a Private Note or posting them on PasteBin?
I have not released any updates since version 5.0 was released (on May 13), and it doesn't appear that there have been any updates to the DeviantArt website itself in that time either.
You may also want to enable the Placeholders setting (if it isn't already). With that setting enabled, you will see the reason a deviation was filtered (either the user's name, or the tag, or the category).
Finally, do you have any other DeviantArt related extensions/add-ons/scripts enabled? Even custom rules in an AdBlocker could be causing the problem you are seeing.