We've had the following situation countless times:

Person A,B,C,D.... are together.
Person A speaks on 2 bars. Person B & C can hear it, but Person D cannot.
They all are in hearing range.
Person A can fix this bug by highering/lowering their voice volume to 3 or 1 bars. If Person A then speaks everyone can hear it, even when they switch back to 2 bars now.

This bug appeared to multiple different people (different people cannot hear; Different people cannot be heard).

We could not find out what is causing it yet.

We had this bug on past patches too, it is not new.
On our server people use the ingame voice chat and radios as only communication, so we encountered it a lot of times already, I myself was there for >15 incidents of this and heard about many more.

This is a crucial problem as Person A can get killed for "not talking/no mic" and cannot communicate with everyone, without even knowing it - especially as some can hear them, they dont think anything would be wrong with their voice for others.