I have encountered several bugs while in a ranked hearthstone match.
I played DH vs DH, 2 times my outcast mechanic was bugged for the EYE BEAM spell. I have 2 screenshots, 1st is when I had eye beam to my far right and it cost 1 mana instead of 0, 2nd screenshot is next turn, I drew my 2nd eye beam and it too cost 1 mana instead of 0. (I can provide screenshots, but don’t know where)
Same game, my opponent used “Skull of Gul’dan” 2 times, and both times it cost 6 mana instead of 5 (I forgot to take screenshots of that)