HoMM3 HD is a mod (add-on) for the game Heroes of Might and Magic 3.

The following bug occurred: both mods were active. During a turn-based battle, when the attacker was about to act, they cast Mass Skin on themselves, but it affected the defenders instead. After that, we started seeing each other's turns on our screens (I could see his Rukh's turn, and he could see my Fae's turn). We couldn't figure out exactly how it happened, but one theory is that during my turn, he saw the wait action of my Fae and opened his spellbook, deciding to cast Skin at the moment I was about to initiate the action. As a result, it seems that both my wait action and his Skin spell triggered simultaneously, but the effect was applied to my units. So, the bug seems to be that the attacker's turn started prematurely, and the defenders' Skin spell was triggered as if I had cast it during my turn. Something like that...