Is it ever going to be called while the processor is active? Or is it part of the configuration stuff, like bus arrangements?
IComponent::activateBus is called in the Setup Done state, the plug-in should be deactivated (setActive (true) not called).
Check here: VST 3 Workflow Diagrams - VST - Steinberg Developer Help
That is a great diagram! Why hadn’t I seen that before?
So, to confirm, would it be a mistake that
IComponent->activateBus is listed in the “processing” state of the audio processor call sequence?
Yes, it was a copy/paste mistake… thanks for noting it… it is fixed now…