Unheard of. The C.O. Glossary flatly states this does not occur:
Dogspeak for “Whut the…?” Frequently accompanied by the Canine Tilt and/or wrinkled brow for enhanced effect. Occasionally, animals which are not dogs have been known to have this cute-ism ascribed to them, but this is never appropriate. Dogs just have the face for it, plain & simple. Cats don’t. Fish don’t. Cockatiels? Please.
Do our eyeballs deceive us?