Well, from what Paul said it appears it is not Qtractor, it is the same with Ardour and basically just any loop connections setup.
Or am I getting it incorrectly? Let's wait for what Paul has to say %)

On Thu, Apr 29, 2010 at 1:32 PM, Ralf Mardorf <ralf.mardorf@alice-dsl.net> wrote:
Louigi Verona wrote:
My version is 0.44, I think. pretty late one, I compiled ot from git in February or January.
I can try another version or another app for that matter. But let Paul tell us if it makes sense at all.

I guess Rui programmed buggy for Qtractor, it wasn't a fault for JACK1 or JACK2. Perhaps 4.4.5+ is needed.