I was playing on Magnet Stones map. And I've managed to kill most of the skeletons mining the magnet stones to their masters (whenever it was possible, I was killing next one - it's a bit tricky, due to huge amount of attacks, but between them I was hunting for one or two). And suddenly, by some reason, I had an error that I've lost! Aand didn't save game and I lost plenty of progress :/

It was the first time when I saw this message, but I have no idea, why? Is there some limit about pieces of magnet stones which can be brought to skeleton masters before I'll lose? That's really odd, because in my opinion I was dealing relatively fast with those skeletons. Not to mention that I'm 100% sure that all my heroes were alive.


Edit: Never mind, I've made second attempt, this time I've managed to kill all "gathering skeletons" relatively early and after that I could take my time and go through mission.