valentine
Auto-translated
It's hard to say why you're experiencing such a strange bug. The first thing I can suggest is to temporarily remove all other maps/mods/campaigns and try starting the mission again (this is the most likely solution, as the loss is recorded upon the death of the main hero, and some map or mod might change the hero's scripted name and break the map's logic). Secondly, try starting the game with a different game profile (but in this case, you'll have to replay the first 2 missions, which isn't ideal).
If that doesn't help, I'll send you a save file for mission 3 after defeating the starting Necromancer in the evening.