its done it before and i turned my phone off and on and that fixed it. wondering why it happens. it only has happened after i downloaded the ios5 software. anyone else know maybe?
I think its a subliminal message reminding you to give your phone a quick reboot... Which is good to do once in a while along with draining your battery from time to time
I have the same problem. It's driving me crazy. I turned my phone off and it worked for a little bit, then not too long after the double notification sounds started again...
The same thing happens to mine. The first sound is really brief, immediately followed by the normal sound. I've only noticed it on text messages. I have the sound set to the default for iMessage, "Tri-Tone".