Not sure if this belongs to bug. But I was playing across Ixalan and my opponent was playing plenty of non standard card. How ?
They were from Amonkhet block.
I bet they hadn’t updated yet.
Interesting… I’m not seeing any Amonkhet cards available for use on my own event. Though it’s possible someone joined the event last night before the standard list updated and was still able to use the Hour of Devastation cards at that point.
Since the app doesn’t force you to update anymore, its possible that they hadn’t done it yet and were using HOU cards. Unless they were playing M19 cards also. then its probably just a weird timing bug