I think I have something figured out finally!
I have had four IPhone 4s trying to rid the proximity sensor glitch. Lived with it each time and waited a few months before trade-in in the hopes that the proximity sensor would be fixed in later model phones.
I went to the Apple store two weeks ago and showed them how my sensor still didn't work and they gave me a new phone again (4th time). They always said don't restore from backup. My last two phones I set up as new and installed all my apps fresh from itunes. Had to enter passwords and lost some user names because I kept setting up as new. I was so bummed when I kept face dialing, even though the genius told me that if I set up as new I would be fine.
So on this last phone I didn't even sync to iTunes. I just used MobileMe to get my contacts and email account set up. I used the phone for a week without any proximity issue
At the beginning of the second week I installed around 5 of my most used apps from the app store on the phone and still had no issues for a week! After I felt I had talked enough without any problems I decided to go ahead and restore from back-up yesterday. Now this morning I muted someone!! After all the experimenting I am seriously coming to the conclusion that it is an app (or maybe two apps not getting along) that is causing the problem. My next step is to set up as a new phone (goodbye passwords and usernames...again! Ugh!). Then I am going to install the 5 apps that didn't cause any problems via iTunes and see if I go back to trouble free operation. If no problems I am going to install one app a day via iTunes until I get to the app that is causing the issue. And when I find it I am going to tell Apple and the developer how much problems this has caused me. In my line of work I can't walk around with earbuds and such on my ears to avoid this problem and it has caused me much grief.
