@Byrdie -  in Midjourney using V4. V3 gave similar odd results as yours

"illustration of full body side view lovely cute happy greyhound wearing a santa hat running through the snow --v 4"

And for this one...

"cute black greyhound wearing a Santa Christmas hat, plain background --v 4"

One of our greyts is a black girlie, but I couldn't imagine her wearing a Santa hat - she's a nutter!! Her bro on the other

hand has a flat cap (like Peaky Blinders) and he's quite happy to walk around and strut his stuff in that along with his matching

tweed jacket :)

Gill