Yepp I have this problem as well. First time there were only 2 parties - me and enemy. Enemy started running away and I got "invalid...".
Second time I rushed to the help of a lord who was fighting 3 sarranid looter parties (united). Some started running away, received "INVALID..." and it crashed.
BUT!
1. Prison break works fine now. Instead of "helper spawned" I receive a lord who actually fights for me and the quest is complete-able!
2. My warriors don't run in circles and I can complete bandit lair quests easily with zero losses. Though they do get stuck into stones.
3. World pathfinding seems much better, though still sometimes moves in an opposite direction (but only for a very short amount of time).
4. I receive more money for prisoners!!!! 80 for some, 112 for others! Didn't try archers/knights yet, still running around bannerless. Also I hope they fixed weekly reports so I can finally receive money from fiefs instead of losing money to army upkeep weekly.
So basically, its much better now!

Now lets patiently wait for this invalid routing behavior fix, I'm sure it won't take more than a week. You still have your jobs and other games, students of all ages still have their exams coming or at least homework to do (trust me, its better to do it than not, I know, I skipped most of it

). It won't be very long before the next patch is out.
I wonder what they'll break next...
