I'm as new as possible with DW.
Before even installing the game (v 1.04, vanilla) I red the manual (common platform info + specific 688i class info). The I also red a tons of tutorials and subsim threads (mainly about DW acustics model).
Last week I made my first single mission, Barents sea loiter.
Set autocrew to every stations, you know, it was my baptism of fire.
Well I estabilished and mainteined contatc with the carrier group in the 19-20 nm range... Was not able to positive classify the destroyers, only the carrier, and forget about the supposed escorting Akula...
I was very paranoid about been heard or positive pinged so I keep distance moving slowly and closing with the group positioning myself behind their baffles while they were moving along their course...
I was so afraid by the Akula (and my own inexperience) that I chosen to attack for the fartest possible range, from behind (I was supposing the Akula would not be positioned behind the group, to me that was the less tactical/logical position for her in the context of her mission).
I know that to completly meet my goals I should be able to sink the carrier and at least damege both escorting vessels, by I decided that just damaging the carrier and coming back to talk about it was a high enough accomplishment for me
So, after 6 patient hours of realtime play

I found myself behind them.
First I spoiled the launch of all my TSAMs not being at the correct minimum depth (was 1 meter below

) then I fired 2 groups of 2 torpedos: 1 couple at the carrier and the other at one of the other two vessels (the one I was able to heard both in passive sonar and in the active intercept).
To make a long story short:
1) I hit something with one of my torpedoes, all the others missed their targets.
2) I was able to escape.
///// And now for the "strange" part
I wanted to know who exactly I hit, with which effect and where all the other vessels were so I turned Truth on. The carrier was indeed hit, one or two of her propellers now dead, she was running in a circle. The others two destroyers/escort, unscathed by my attack, were running in bigger circles around the carrier. One of them in clockwise direction, the other in anti-clockwise direction.
I was going away slowly and silently, with a growing sense of satisfaction cause my attack indeed hit the carrier and (in a roleplay sense) was truly a success cause the russian operation was spoiled, my crew was safe, and my boat undetected (well, more or less)
I was preparing to hit the "End Mission" button when a message informed me that I had done a great job completing the mission objectives destroying or damaging all enemy surface platforms.... WHAT???
I checked and the two escorts were no more to be found, only the damaged carrier remained, still helpless circling. It look liked the two genius destroyer commanders collided with each other vessel in theirs zealous, absurd, reciprocal CW/anti-CW circle patterns around the carrier... or at least that's what I think did happend. I do not have a better explanation.

...
Anyway this fact steal away from me any sense of sactisfaction, and even if me and my crew were toasted on our triumphant return to the base the whole affair felt strange at best.