Did you check if you had Armor Class or not?
In my experience I tried many times and discovered this:
- If I get the AC bonus at the end of turn, and I have it around 100+ there is a large chance that enemies start to escape. After a turn or two, they freeze and start to cycle all the "taunts" they have, very fast, until their turn timer expire. This seems to affect ONLY humanoid enemies, not animals, mutated beasts or else.
- If I negate the AC bonus or I have an AC under 100, this bug doesn't happen.