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Are you playing the original version or do you have mods installed?
You should understand that mods and maps (mods) can affect the gameplay of the scenario, leading to crashes. If you have fan-made mods and maps installed, leave only 1 of your maps in the maps folder. As for mods, remove those that cause conflicts.

Added after 43 seconds
In general, the scenario is working. There should be no crashes.

I don't use mods at all, including EWA. And I often use quick saves. But I noticed that this bug is not only with this map. Today I was playing Hammers of Fate, and in the 4th mission, when I was going to Thor Hall with Freya and Laslo, the city suddenly started being attacked, and the game also froze, so it's not the map, fortunately.
I started the map again on beginner difficulty and completed it in an hour, just to watch the final cutscene.
Now I'm starting a walkthrough of Unicorn, RedHeavenHero, you have wonderful skills, wonderful maps, and a wonderful campaign. As I understand it, you won't be making huge projects, but what about one-off scenarios?