Well, spotting is not totally free of bugs. Had a game a few days ago, where First i was Stuck at the loading Screen for minutes and then, wen i finally got to start, i sag an Echo of an enemy destroyer approaching on the minimap... he stayed detected but invisible until he was about 1.5km away.
I was in a kawachi, so needless to say, i ate a lot of torps and sank.
Probably was a Performance issue with my computer, but still seemed strange.