Headphones mic not working

In whatsapp, skype, audio recording apps and regular calls the mic on my 3.5mm connected headphones isn’t working with the FP3. And in whatsapp video calls, the sound comes from the side speaker, rather than the plugged in headphones (or ear speaker for that matter).

They work as expected in other android phones running Android 6, lineage 15.1 (Android 8.1) and lineage 16 (Android 9).

Has anyone else come across this issue and, hopefully, a fix?