Contact Ring Tones Reverting to Default

Having an issue with ring tones assigned to contacts. I assign ring tones to contacts for phone calls, email messages and BBM. Eventually, usually after a few days, they all revert back to default. This has been going on for a while, and it seemed like the problem was solved when I installed the leaked OS (10.1.0.2354), but about 3 weeks, all of my contacts' ring tones have gone back to default.

I was wondering if anybody else has experienced this problem, or had a possible solution. It's very frustrating to me.