Here is an issue I discovered with the 90bt paired to the BB Bold 9000. While on the phone...

 

1. new call is received

2. second call is answered (first call placed on hold)

3. second call ends

4. Switch back to first call

 

90bt audio source activates along with phone call. I have to turn the 90bt volume down to isolate just the phone call. This seems like a bug to me.