Strange microphone issue

[dinabashirian]

Hi guys,
I seem to be having a strange microphone issue on my iPhone:
When I am making normal phone calls, nobody seems to be able to hear me. When I am making calls through WhatsApp or other apps, it works without issues.
Any ideas where the issue can be at?

 

[Alan Bourdillion Traherne]

Overmodulation of the super-heterodyne framisters. I'd have it looked at.