I loaded up my 3 champs for the first round of arena grind. Then got called away for a while, before having any fights. Over an hour later, got back to the arena. Before this latest update, my champs would have been still sitting in their slots, waiting for fight round 1. But now they show as being on cool down, despite not having fought with them. This is a bug.
Device: latest iPad Pro
Game: latest version
iOS: latest version
Connection: wifi