I've been messing around with Coin of Many Faces and it seems that cats don't want to sit on the lap when a character is transformed by this item. The original characters are fine.
I haven't tested transformation from other sources, maybe it's worth a more deeper investigation.
Of course we don't talk about druids, shamans or worgen, okay?
(On the other hand, it would actually make sense that a cat doesn't trust an unfamiliar shape. Like they ever trusted the familiar ones anyway.)