Sanyo M1

I am having the same issue!!! It seems that it happens after I hang up the phone by closing it.....if I press the END key, I do not have the issue....I called sprint and they have not heard of the issue. The other issue I have is if I have speaker phone on for a few minutes the battery starts beeping telling me its going to die soon.....yet I can talk for hours after that. Your/our issue gets annoying.....only thing I can tell you is to hit the end button before you close the phone!