It seems to work ok for the scenario/campaign (played the first map and there were no crashes after obtaining the head). I will try if the problem manifests itself if I give the head to my capitol (was giving it to the town with most grain).
Edit: It seems to work fine now...also if I award the head to another city...don't know what changed. These are the only things I did:
- Played the first scenario (till the end)
- Loaded the old save, did the fight with Amhah, awarded head to capital -> worked (used a new save!)
- Loaded the old save, did the fight with Amhah, awarded head to the same city it crashed before -> worked (another new save)
- Saved again on old save -> worked.......???
Does the campaign change something in the game config so you have to start the campaign before the head of amhah works flawlessly?