I sunk it 3 times. Every hit done at Med., last QM co. CN 66 and near Tripoli. It seems to me her route is from Tripoli to or via Gibraltar.
As it was written above, QM is suffering from a strange bag. When QM is spotted via pericope ora via external view (F12) it stops engines. I confirm, and there is no doubt, that QM is moving. As I recall everytime QM sails in small convoys along with Pasenger Liner (23-24 000 BRT) or CHT Liner (about 5000 BRT) and 2-3 marchants, and 2-4 escort ships. In the meantime in my 29 patrol I'm about to attack QM (near Tripoli - about 150 km North), so the "problem" is hot for me.
I can't confirm however one hit sunk possiblity. I did used only one torp on QM to destroy it, but - I must confesse - I'm using tweaked T VII

(this baby can sunk a KG V in one shot no matter where it'll hit). The bug is annoying, because QM stops many km away from a convoy, so I have to make two different torp attacks instead of one, and everytime it ends with pings and deaphtcharging from escort DD's for about 1 hour or 1,5. But it is still worth it.

And if you .... need some sreens - just ask and I can upload some (after I learn from sticky thread how to do that) for you.