I have a strange occurrence that is annoying my users. When one extension calls another extension, the system is configured so that the extension rings (not intercom). The user answers the call using their SPEAKER PHONE, they have a conversation with the calling party, the conversation ends and the CALLER hangs up, the extension that was called then hears three or four busy signal tones over their speaker before it disconnects.
This only happens when calling extension to extension and it only happens if the user being called answers with their speaker phone.
Any ideas on what is causing this and how to stop it?