MArcomage

Unfortunately, I can't find an older replay to justify this, but when Avatar of Vengeance was changed to have the rebirth keyword instead of the durable keyword, its behavior when targeting itself changed. Before, when targeting itself, Avatar of Vengeance would not be replaced by the matching card. Now, it is, even if the rebirth keyword triggers. Here is a replay that demonstrates the current behavior:

http://arcomage.net/?location=Replays_details&CurrentReplay=405175&PlayerView=1&Turn=67

Was this change intended?

Yes, it's working as intended. The card execution is the same as before, but the new log-based system is showing what really happened. The previous diff-based system wouldn't show the discarded Avatar, because it only compared your hand before and after the card was played. This would yield no difference and thus you would not see the discarded Avatar.

I was referring to the part where Avatar of Vengeance was played, transferring Librarian to its position and overwriting Avatar of Vengeance. Before, Librarian would have not overwritten Avatar of Vengeance.

Yes, I see now. It's definitely a bug, I'll add it to my TODO list, thanks for reporting.