Using my new Motorola HK375-S headset for phonecalls the recipient of the call experiences a buzzing sound at the end of each sentence (when I go from sound to silence).
It is annoyingbzzz For the recipient I meanbzzz
The problem is with my Fairphone 4 because I experience the problem calling my wifes phone using the headset on the FP4, but not when using the Motorola headset in her Samsung S8 and calling my FP4.
Or rather it is there if you know what to listen for, but much shorter and negligible.
My Trekz Titanium headset doesn’t have the problem, but its microphone is not great. That’s why I bought the Motorola headset 
I have tried turning HD audio off. The problem gets worse.
I have updatede my phone and rebooted. Currently running Android 12. The problem persists from Android 11.
The only codecs the headset accepts is ACC and SBC. The SBC option doesn’t solve the problem and makes the sound worse.
I suspect the cVc noise cancellation could be the cause, but only because it isn’t present in my other headsets.