The Hero's Path

Yes, the battle was clearly unwinnable. I think I should introduce a limit that prevents players from entering the arena if the army's strength is significantly higher. On the other difficulty levels, do the enemies at least deal some damage? With attacking spells, heroes have a real problem; I don't want to force these things with scripts, but no matter what magic I give them, they still refuse to use them.

Regarding the deployed units, I suggest you first try loading a save file – if it works for you, it will be the easiest way to find the bug. You can also start the map from the beginning and immediately try deploying someone – to see if the bug occurs during the game or if it's an inherent issue.