Stealing a Unit and Overflow Killing it Causes Legacy Effects In Favor of the Opponent
This probably isn't a bug but more unexpected logic that can backfire in your face. If you take control of a Unit from the Opponent's side while you already have a full board, it of course dies, but if it has a Legacy effect, it will trigger in favor of the Opponent as if it died on that side. I suppose the logic is that the Unit never truly summoned on the attempted usurper's side of the field, therefore it technically died on the original owner's field.
Definitely a rare situation but I thought I'd bring it up in case this was an unwanted scenario.