Yesterday in one of my matches if i remember correctly i saw a kobold miner excavate twice i could be wrong - i think i stil lost the match but it was weird unless there is a interaction i am not aware of in game.
Obvious question first : were you against a warrior ?
There are cards/effects in the game that make battlecries happen twice.
So probably, your opponent had played one of those and you didn’t notice.
This was in standard and i think i was facing a paladin but not sure though i think it was a paladin.