I usually turn the tuner on between songs. For the next song I switch to the desired preset. When I do this, the preset should change and the tuner should go off. All my previous digital preamps (Line6, Roland/Boss, Fractal) behaved this way.
With the QC, the tuner goes off when you switch any preset, but the last selected preset remains active. This makes no sense.
When using MIDI, the tuner remains active and muted even after changing the preset. This is pointless and annoying. If I forget to turn off the tuner, I start the next song with a muted signal.