This can sometimes happen when you play against AI. I originally only identified the "it sometimes breaks" problem and not the root cause. There already is a mitigation that will reload the page after 10 seconds of inactivity. Felix identified how this breaks and shared a way to reproduce it.
I think in my game it crashed. I think I picked up a union on Hedwigs turn. Before Hedwig was able to move.
It was an accidential double click.
Then it reset itself
It appears that this got fixed together with #126 by 402bbb80bec8962bc1a80d53f29fa5cbc690660e at least I can no longer reproduce this problem. The reset code remains in place.
This can sometimes happen when you play against AI. I originally only identified the "it sometimes breaks" problem and not the root cause. There already is a mitigation that will reload the page after 10 seconds of inactivity. Felix identified how this breaks and shared a way to reproduce it.
This goes together with #126