No 100% sure what happened. I was trying to get my Hearthlings to stop standing around by using the party to go to an area. I think it started when the encountered some goblins outside of the village walls. I have a screen shot but I can’t upload it. Here is the link to the screenshot. The error seems to be in a loop now and won’t stop.
Hope this is helpful.
hey there @Odontoblaster… welcome aboard! 
I tried to embed your image, but apparently Google didn’t want to play nice… 
I’ll see if I can fix that later when I’m back online…
So I tried the same thing with my saved game. (Thanks for that by the way) And it definitely had something to do with engaging the Goblins that were clustered outside the village due to having walled things off. I got the same error coming up except this time the game crashed.
I had the same thing just happen to me, but it was when the goblins killed off one of my footmen. No walls or anything around the town either…
From what I have observed if you completely wall off your village the game will loop spawn goblins in 4 points around your village, if at any point you try to kill the goblins you will end up with some form of this error whether you actually get the error message or not depends on if anyone dies. If I had to hap hazzard a guess as to a way to fix a batch of issues I would say to add an exception into the goblins programing so that if it can’t get to the stockpile they spawn up to a set number then stop spawning and then only check to see if they can get to the stockpile once every so many minutes so that you don’t end up overloading the pathfinding script. If you don’t go that route then you need to make it so that if the goblins can’t reach the stockpile due to fence then they attack the fence until they can get through.