For some reason when you set a stop for a phase while you are in the phase prior to it, Arena does the exact opposite of setting a stop. It auto passes priority ignoring all triggers regardless of if you could have acted or not. losing games to this bug is super frustrating and this bug has been in the game for a long time now. in the screenshot attacthed you can see that I had set an upkeep stop in my opponents end step to ensure that I can cast swords to plowshares on my own Phlage to gain enough life to not die to my One RIng trigger. to my dismay Arena auto-passed through my upkeep killing me without even giving me a chance to cast my instant speed spells and giving my opponent a win for a game I had full control over. I take ranked games fairly seriously and decided to finally report this bug as it has cost me many games. However it would usually occur in less vital moments. straight up losing the game to a bug is not okay so please do something about this. As a developer myself I believe it must have something to do with whatever system is responsible for the levels of contrl in the game system. if it is flag-based I have to assume setting a stop must force the game to increase the level of control or flip a boolean or something. the problem is likely that the game automatically increases the control-level when the player could respond to vital triggers. My suspicion is that the games automatic control-level change makes the control level overflow when a stop is set and makes it end up being the lowest control level (auto-pass). And yes I would love to work on the Arena dev team...