Suspicious alchemist bug

So I had an explosive rune as a secret, oponent plays suspicious alchemist, they discovery a spell - > explosive rune triggers kills the minion – > I don’t get to chose what spell he chosed so I can get a copy.

What is this strange interaction ?

There have been more reports that all seem to suggest that the opponent guess part of Suspicious Alchemist requires that the minion is alive (and untransformed) on the board at the start of the opponent’s turn.

Whether intended or bug is at this point not known.