priority
Opponent Edwatho abused Scurry Oak and Ajani's Welcome and Heliod to go off in response to my Storm the Festival while I had lethal mill instant speed available. Game NEVER showed my timer running. When they ran out of time it skipped my entire turn without ever giving me priority or even resolving my spell. I suspect this was an intentional exploit creating a massive stack with well over a hundred abilities in order to prevent me from resolving abilities to kill them. I believe the size of stack was intentional to trigger this bug.
Won't let me attach the log file as either it's full size or in zipped format. To reproduce put skurry oak, heliod, and another etb life gain effect on the battlefield and click on skurry oak as fast as you can not letting the abilities resolve and let the stack grow to a massive size seems to eventually skip the turn