Some enemy NPCs don't flee and persist in fighting
There's a very confusing issue with this NPC: https://elderscrolls.fandom.com/wiki/Jeanciele_Macile In the vanilla game (every time I test his behavior) he will run away after summoning an ancestral ghost. Notice that he's a witchhunter and has flee 70 and fight and alarm are 0, and he resides inside a room near the vampire smith in Ashmelech.
This how I tested it and what happened, enable god mode and don't attack him btw: Entered the room where he resides and let him summon the creature, then follow him until he reaches his destination, open a trapped door or a locked door for him if he gets stuck there and keep following, you'll see he reaches the boss vampire's room and then run away from you again to another place. Everytime you kill his ghost he will resummon it again until he can't, and everytime you get close he flees, this is the exact result for the four times I tested this.
In OpenMW he will summon the creature and doesn't run but will cast vampire's touch spell until he can't and will summon the ghost everytime you kill it, when those spells run out he will use hand to hand and will persist in fighting the player character, this the result most of the time. Sometimes he will try to run away if you give him space but he returns immediately for everytime I tested (10 times).
On the other hand there's another witchhunter NPC named Odmi https://elderscrolls.fandom.com/wiki/Odmi In the same dungeon (Notice he has flee, alarm and fight 0), in the vanilla game if you don't attack him and let him cast vampire touch and summon the creature he will continue until his magicka runs out and then flee (Will successfully flee) but if you get close to him and he's stuck he will attack using hand to hand. But in OpenMW for everytime I tested he persists in fighting the PC.