Just one (static) waveInCriticalSection but multiple QAudioInput to record from different soundcards

I have an application which must be able to record from different sound cards.
Here it comes to a problem with the waveInCriticalSection in QAudioInputPrivate.
For now my application keeps crashing on exit cause one instance will free the critical section and later the other instance tries to

EnterCriticalSection(&waveInCriticalSection);

cause there are still data arriving for the other sound cards.