I have been having this problem with any firmware based on stock .290 and .136. Be it Whatsapp or Line or Viber. Anything that sends an Audio message comes out garbled, which is extremely annoying.
The weird thing is.. this becomes PERFECTLY fine when I open the the SIM card port.. I seriously fail to see the connection to MIC performance here.. with the port being open! so it's just weird!!
I have downgraded to .257 for now due to this bug.
Can anyone on .290 or .136 try whatsapp audio messages and see if the problem exists for them too?