I was playing as Terran Warrior verses Terran Shaman. Played Boomboss Tho’grun near the end of the game. He was not copied, stolen, or anything and somehow 3 bombs ended up in my own deck. Upon some research, seen this was a bug almost a year ago but never seen this happen recently or to me.
A replay would be helpful in those cases.
When you drew one, did you inspect the game history log to see how it was created?
Adding to the comments above, was your opponent’s deck empty?