1. I am subscribed only to the main mod and to the asset pack.
2. Resubscribe doesn't work.

Which settlement was it?
Skeggi (also happened in Teotiqua on a different save under same circumstance)

Did this happen on Mortal Empires or Vortex Campaign?
Eye of the Vortex Campaign

Which race was defending & which race was attacking?
I was defending with Lizardman and the opposing side was Norsca

Were you defending or attacking?
Defending

Did either side have reinforcements?
Norsca was reinforced by the garrison

Was it a walled or unwalled settlement battle?
unwalled

When did it crash, exactly?
No crash just a bug

Did it show a battle preview before crashing?
Again, no crash occurred

Here are some screenshots of the problem:
https://steamhost.cn/steamcommunity_com/profiles/76561198081089142/screenshots/?appid=0&sort=newestfirst&browsefilter=myfiles&view=imagewall&privacy=8

This happened after encircling/sieging the settlement for 1 end turn phase then being attacked. Should be very easy to replicate as the mentioned settlements are very close to the starting locations of both the lizardman and the last defenders.
Also this problem only happened on Eye of the Vortex campaign and not a Mortal Empires one.
If this is a fixable problem then that would be much appreciated. If not and is a problem on my end then advise would be welcome.

P.S. This mod as whole is great and I love the work that you are doing. Keep it up and good
luck for the future.