[2020] I've updated the definition of "stealing" by bouncing opponent's THG to my hand (spoiler: I don't own THG)

Yikes! Last time we had a bug like this it was for [[Discovery // Dispersal]] where we had some weird anaphora resolution stuff happening. It's hard for me to see how [[Petty Theft]] could go wrong... Can you clarify a few details?

1. Who controlled what before all of this happened? Was it: you had Thassa and Agent of Treachery and has cast one spell, Chimerekt had Fires of Invention and The Great Henge?

2. Was there any strange way that they put The Great Henge in play, or did they simply cast it?

I'll try to dig into how the game either got confused about ownership or which destination to put the Great Henge into when you bounced it. Thanks! #wotc_staff