UPDATE: I thought for sure I had tried a hard reset (holding down the home and power button for 10 seconds), but when I tried it again, it actually fixed the problem!! It hasn't happened again since! So for anyone else still experiencing this problem, I highly recommend the hard reset.

UPDATE: Okay, so I could have sworn I tried a hard reset before, but seeing your message I figured it wouldn't hurt to try it again. Wouldn't you know, it worked!! No more double tone every time i get a text. Thanks for the suggestion!

I too am having this problem, and have reviewed ALL the forum postings I can find on the subject. Some have asserted that the problem is resolved, but it IS NOT. I have tested ALL the possible settings and configurations, including changing the "Repeat Alert" setting to "Never", but the...