This is a known bug, different card art cards always turn into the left most premium card, they'll probably fix it soon

Happened just now to me, hope it gets fixed soon.  

Same here :( but ive got the rightmost reaver hunter in premium from keg so my premium rh collection is closer to be a whole :D

I crafted one of each Reaver Hunter cards and then transmuted each of them (100% sure I did NOT transmute 3x of the same card), but when I went to deck builder I had 3x of the same Reaver Hunter with the same animation.

What the fuck?

I had one of each Reaver Hunter, transmuted them into premium and they all turned into 3x of the same???