Using phone speaker during call works only for a little while

[joerund]

While talking on the phone using the loud speaker, it will only work for a few minutes before the person on the other end cant hear me properly and the voice gets scrambled. This happens with everyone Ive talked to - so its not an isolated issue. When switching back to the reglular phone speaker it goes back to normal again.
The phone is usually on a 5G net when this happens.
Anyone else with a similar issue?

[dron39]

I have same issue out of the box. Don't use 5G but it happens to me each call. By the way doesn't matter if it's phone call or whatsapp/viber and etc.
You can try to lower down to minimum speaker volume for test - it will help. But of course it's not usable in real life.
Has you bootloader been unlocked?

[mkumitsu]

I have the same issue as dron39. What's interesting, recording audio in videos work properly. Only during calls on loudspeaker this happens. The caller hear only part of what I'm saying. And it's also since I remember.

[dron39]

If you have warranty - then it's better to go to service and calibrate some settings there with their software. But it's better to show your issue instead of send device with problem description. Mine was returned with "no issues are found". But when I called to service engineer phone he noticed issue then. Maybe one of the MIC's are defected (there are three of them in ZF8).
And i want to ask you again, has your BL been unlocked?

[joerund]

Thanks for the feedback. Its not rooted or anything, just a regular out of the box phone. I have had it repaired once already. Will just hope a firmware update might cure it and make it usable.