Welcome,
Is the issue that only VC1 is getting callbacks, or is it possible that VC1 and VC2 are simultaneously getting callbacks from the same speech but you are reacting to the callback in VC1 first and not getting the info that VC2 is also getting the callback? The expectation is that they would both get a callback from the same speech event if they are both instantiated with OpenEarsEventsObserver delegates.
Second question is about what is being set to nil. Did you set FliteController to nil, FliteController’s OpenEarsEventsObserver, or FliteController’s OpenEarsEventsObserver.delegate?