[Aufklarer]

I dont think that these were built into the game, and it does seem as if the AI has gone a bit mad. Treating them as if they were 'Q' Ships would seem the best solution. Also I think its not actually a bad thing, The AI throwing a curve ball at you keeps you on your toes, having them react in a different way to what you expect can add an element of suprise and fun to the game.

Who is to say that when briefed about their convoy crossing the ships captains were told "Ok guys if we come under UBoat attack i want everyone to cut engines and the 'Q' Ships go see if you can coax that sub to surface!" New tactics were implemented all the time by both sides in the war, constantly trying to remain one step ahead of each other.

The fact that the merchants seem to circle your position indicates that they had some sort of detection equipment, which isnt strictly accurate but aslong as the game dosnt throw that out everytime then i would embrace it with open arms, an unpredictable enemy AI is what we always wanted!