That's covered earlier in the thread with a before and after photo.
That's a bandaid. The parties within that army would otherwise be able to recruit more units or fight bandits or something.
I played a bit in the 08/02/21 hotfix and as far as I could tell, it was resolved.
I should be able to find a little time in the next 24 hours to do that. I'll update you on the matter soon.
I created a separate thread. It's in work. Thank you anyways, uçanbiblo.