I just had a Softlock in Avacyn’s Madness 4.3 after Greg used Engulf the Shore. In the previous turn my side of the board was full with 3 creatures. Niv-Mizzet Reborn, Utvara Hellkite and Lathliss, Dragon Queen. Lathliss was reinforced because she is a leader.
Why are you running an event that causes softlocks that you are aware of? You know that returning reinforced creatures can cause softlocks and yet you decide to run a PvE event where the AI has a card that returns creatures that could be reinforced.
This is the link of the video:
This is the link with the deck I was using:
Dragons Dragons - Album on Imgur