Closing/exiting Qtractor hangs sometimes

I use non-mixer-xt to host several reverb plugins. This distributes the realtime load with genuine jack2 to several CPU cores.
And I started to use external hardware, e.g. compressors.

I use audio Insert Sends to connect to non-mixer-xt and external hardware.

With complex sessions I noticed a strange behaviour that I cannot reproduce in a simple test session yet:

• Closing (close button of main window) or exiting (File->Exit) hangs sometimes.
• Other running jack-clients like non-mixer-xt or Qjackctl are also hanging and cannot be closed/exited
• I can kill Qtractor with the session manager or a kill command, then the other jack-clients end

It seems to help when I deactivate those Insert Sends before closing Qtractor, especially those that go to external hardware and back.

Would it be a good idea if Qtractor was deactivating all Insert Sends before disconnecting from jackd and exiting?
At least it cannot hurt, I guess.