Proximity sensor and end phone call button problems on replacement iPhone 4

[punisher1-1]

I recently exchanged my iPhone 4 at apple because my home button intermittently would not respond. On the replacement the home button is great but it seems like I am having proximity sensor issues and sometimes I am unable to press the end phone call button. I restored from backup since my other iPhone wasn't having any problems other than the home button. I don't want to do a full restore because I don't want to lose my saved game data again. According to the serial number it was made in 2011 in week 22 so it's not the old batch that had the proximity sensor issues. I really don't want to return it either I just want it to work. Any tips on what to do without a full restore. Hopefully iOS 5 will fix it but it's kinda annoying in the mean time.