Hi,

The pocket 2 has 4 microphones built in.
However when I listen back the audio when editing the video (Windows - Davinci), the audio sounds sometimes mono.
So when filming on eg. a market square in a city, I first hear the spatial/stereo sound of the people walking around me, which sounds real, and later the recording can sound mono, which sounds flat.
And I am not covering microphones.
What can this be?

I did not use the pro mode (yet), just the auto mode.When there is some wind, it looks like the audio becomes mono again and later it becomes slowly stereo again.Just if the side microphones are turned off and switched over to only the front microphone.

Yes, that is the wind noise reduction working.  But sometimes it is triggered by low frequencies of other kinds, for instance if the camera is used inside a moving vehicle.  I think that in future firmware, this could be adjusted a little to discriminate between wind and low frequencies.  Of course you can turn off the wind noise reduction, but that might make matters worse overall.