I can't believe people are actually against fixing this bug one way or the other
This has nothing to do with the TA being cut because the sub is going too fast or doing crazy maneuvering, even if you change depth at 2-3 knots the TA is going to be cut.
For one time, just ignore the people critising this crucial bugfix because of a cosmetic issue.
Just play with 3d view disabled and your sense of estetics will not be harmed
Until SCS fixes this in a patch, I urge you Luftwolf to fix it in the 3.0 mod please, please, please.