Cats in a 1 block high gap will not sit/stand

Does it work with that cat when it's not in a gap like this?

Cats function normally when not in the gap

I asked about that one cat that you found the issue with.

When cats (all cats) climb into the gap they will automatically sit and cannot be restored to the standing position.. I had to break the block either above or below to release them. Hope that makes sense.

OK, it may be that the issue relates to chests and not necessarily just the 'gap'.
When a cat sits on a chest it will automatically sit and will not return to the standing position when 'clicked' Also, the corresponding chest cannot be opened