I did do a few additional tests-- here's what I've found so far:
1. Call button pushed and answered by VTH -- NO RECORDING
2. Call button pushed and answered, record button pushed on VTH-- NO RECORDING
3. Call not answered, no message left -- RECORDED SUCCESFULLY
4. Call no answered, message left-- 2 Clips RECORDED SUCCESSFULLY -- 1 before the message while ringing, 1 for the message itself