Shattered Kingdoms

I have an idea that the concentration bug (the one that logging out fixes) is caused by no-magic rooms.

Why is it so hard to use the bug/idea command for that?

Because, *gasp*, I thought others might have something to contribute to this conversation.

Whining about proper use of the bug command does not count as contributing, by the way.

I strongly agree with that assessments but we need to narrow it down a bit more than that.
I think it might also has to do with you having spells up on yourself and someone else at the time. Something like your list gets wiped in the same move as a spell is cancelled or dispelled by no magic, just before or just after. One causes the bug the other doesn’t, which is why it is so hard to reproduce. It might also have to do with a tick timer going off close to or at the move.