Pinging from Dead Ships!

[Captain Nemo]

I am currently playing a mission where the ultimate goal is to sink an aircraft carrier and destroy the port that it is moored at. I am driving an LA class sub. The carrier is heavily defended by surface ships as well as a sub (Akula I think). Anyway, during the course of the mission (which is damn difficult, this is about my 20th attempt) I have sunk a couple of destroyers. The odd thing is, in DW the wrecks normally disappear after a while (known bug I think), but in this case they haven't done that and after a while they have started pinging me with active sonar! I am still playing the mission so haven't used show truth to verify this, but if I am killed (most likely) or complete the mission I will try and confirm it.

I know this was an issue in SC which I believe was fixed, has anyone else experienced this in DW? I have been playing DW for some months and this is the first time I have seen this.

Nemo