this is a old bug that sometimes came back , and is a real bug becouse hard blocks a part of the game and ticket support can’t do anything.
So blizzard have to consider a general workaround like putting a Retire button on all stages of a duel , from hero selection , to deck creating screen , bucket selections, etc. at least one can clear this situation , who cares losing a good run if you cant play duels anymore.
I think they dont put the retire button to force a player use the 4 random class , but people hunting for a specific class will start first game , concede , and retire …
in the past they suggested reporting using this link dont know if still works
Use “Contact us” under 3
If you see nothing is solving , try contact/tag @fusrohdaniel on twitter