Weird AI behaviour

[archer9]

Coastal Waters campaign, Nothern Approaches mission, Open Horizons II mod. I've noticed some weird stuff happening. Sometimes I get hunted by a single escort that appears out of nowhere (feels almost like it's scripted). It's as if he knows exactly where I am and comes straight for me from behind even if I change my course. (I've had this several times, annoying as hell.) How does he detect me and know my exact location from 6000 meters away?

Other times, after sinking a capital ship, the escorts search for me for a while. I silence the uboat and keep it at 100 meters depth. The escorts all go away, except for one who keeps spinning in circles approximately 1000 meters away from me. At night I surface and slip away. I am far enough to run at max speed and I am positive I can't be seen or heard, yet it keeps chasing me for some 1000 kilometers, keeping his distance of ~8000 meters, spinning in circles, then going straight a bit, then spinning some more. What. The. Hell.

My mod list, if needed: http://i.imgur.com/H3cJZmx.png