BUG Strange Noise when Transferring Calls

[Darryn Shilling]

Raspberry Pi ver 3.11. running 2 SIP trunks and 4 extensions. When a call comes in and is answered no problem the audio quality is good. If the call is transferred to another ext or to an outside number there is a loud noise like BRRRRRRRRRRRR!. This also happens when the incoming call is handled via an IVR. The IVR message is clear then when an option is selected that sends the call to an onsite ringgroup or to an outside number the same noise. It is almost like a feed back noise but low Pitch. I cant for the life of me work out even where to start looking for this? Any ideas would be greatly Appreciated? I should note that after the call is connected to the other number an or ext then the audio quality is fine. the noise is a short 1-2 second blast.