Echo issues during phone call

[tmpneuf]

Since 2 weeks, every receivers can hear themselves twice, like an echo. The problem happen only when I'm using the internal microphone. It work correctly if I use an wired headset, bluetooth headset or the phone loudspeaker.

I tried to repair the phone with Xperia Companion but nothing changed. Do you have any idea of what it could be?

Thanks

[Uliwooly]

@tmpneuf 

Test the phone in >>> safe mode  just to see if it's a third party app acting up

[ClareV]

I have the same problem with phone call, tried also the safe mode, but doesn't work. The problem start when my phone came back from assistance, upgraded to android 9..

Thank you