I have never seens this kind of bug in this game at the final battle Oo... is the game installed on a SSD or is there a patch ???
From what I can speculate, it's a glitch when using Resurrection when two (or more) dead, 2-hex units overlap with each other. In the video, the main problem was where the spell was casted. Griffins overlapped Hydras so that three hexes were occupied, then the spell was casted in the middle of the two units. The game didn't know which to prioritize, so I assume it tries to act like both are resurrected.
The other problem (that I didn't expect) was the unit of dead Minotaur Kings underneath the Griffins. So, what happens when you try to resurrect a dead unit that is underneath a resurrected unit and that resurrected unit is supposed to not be resurrected? Um, I don't know. As we see, the Minotaur Kings were made pretty much invincible; they can attack, you can still target them, but you can't damage them. So the battle is essentially soft-locked.
This is such a niche glitch that I can't believed worked out like that. I dreaded the spell RNG going into the final fight before, but if you wonder why you should worry about how units are positioned in a battle, this is it. At least now Heroes of Might and Magic II can be placed in the category of "World Records with 'This Has Never Happened Before.' ".
Similarly, this happened to me once when there were Phoenixes over lapping with Dragons; I got two bands of Phoenixes in the battle that way. The Dragons are immune to magic, so thankfully this did not soft-lock that battle.
One more thing to think about in the last battle for sure then. So many minutes could'v been shaved of that last map. Road to sub 1h has begun!
