[Mrbonner]

Sounds like a Voice Command issue. Each time the volume decreases is when voice command is supposed to announce the callers info. It hasn't worked for many people since launch and I dont know if theres a fix for it yet (Is there?).

Any rate go to settings, then voice command.
In the menu box, scroll to phone. Click on it then click notifications to the right.
U can set it to announce using bluetooth handsfree only and check during free time.

Should solve the problem.