Problem with CM12 based ROMs topic

One issue that I have is that sometimes the speaker cuts out during a call so I can't hear anybody. I have to put the call on loudspeaker and then off again so I can hear them. It also seems to cut out if I bring the number pad up as well. I've had this on 2 CM12 based ROMs - Candy5 and AICP - and it happens with both of them. I've just flashed a stock based ROM - I don't like stock based ROMs - and I don't have the issue.
Does anybody else have this problem? I'm using a D855.