[Dive! Dive! Dive!]

I have the same problems. I understand most of the games vehicles are somewhat buggy (eg DSRV) but I think it is more to do with torpedoes. One time I engaged a French ámethyste submarine and it worked fine (Udaloy with RA mod but mechanics are the same.) But on occasions the torpedoes would target me! I took a few hits from torpedoes when my ship was atleast a few miles away. My best bet is to only engage solitary targets where there is no other contacts nearby.