Beastmen attack Bogenhafen - freeze

I just had a quite peculiar freeze:

Playing as Reikland I am holding Bogenhafen which is scripted to get attacked anytime after round 50 if Reikland (hre) holds it.
The Beastmen army spawns, at the end of my next round they move to siege the city and at the beginning of my next round they attack (attack screen with choices appears) - which causes a freeze in all movement on the map and eventually a crash.

My concern now lies with the scripting: the attack is scripted at the beginning of MY turn - not sure if that is the cause of the problem, because usually it's scripted for the attacker's turn.

Has anybody come across that problem?

I was attacked in the beginning of my turn twice when playing as Stirland. I didnt even know it was possible. I was attacked once by sylvania and another time by beastmen. I didnt have any crash when those attacks occurred. I dont know about Reikland.

Thanks for the feedback, can you recall which settlement was attacked by which faction?

Cant remember exactly which settlements were involved, sorry.

I isolated the script part and tested it in a reduced script without problems - guess something else must be playing into it, maybe one of the historic events firing as well at the beginning of the turn.

I'm having the same problem in turn 8 with the dwarves. Night goblins are attacking 8 something castle ( southernmost dwarf settlement) and i'm getting "great beards" at the same time and the game keeps freezing. I can't auto-calc, fight on map or anything. When i tried to fight on battle field the area it zoomed into was in the middle of the map on a city i didn't see.

Any help for those of us non modders so we can we fix this would be very much appreciated.

P.S. Also got the "Great Rock Anvil" once or twice.

It will have something to do with other stuff running in the background of the game - I have not been able to continue that game, nor being able to determine what might have caused the problem.
In a new game other spawns with siege work perfectly fine.