I do remebmber that happening with a 3000 series phone some time ago. I know if you pickup the handet you can hear out of bot headset and handset. I wonder if it is related to the lifter picking up the handset, because I have not hear a complaint recently.

I have read that there is soemthing you can cut, at least in the 3000 series phones, when the phone is eqquiped with a BHUE and headset. I have never cut it. Something I don't like about making permanate changes to the phone.