I have this problem on the TBolt sending to my wife's EVO on Sprint. But it's not consistent. Just occasionally.
Dammit it's annoying as we can't pin it down as to why she's getting multiples. And every damn one of them is counting against my 500. I don't need more than that if each one I sent only was sent once!
I do not and have never installed Astro File Manager. I do have AndroZip File Manager installed, but not Astro.
I also do not have Handcent installed nor have I installed it since I did a factory reset just to clear out the crap I tried out.
I just did the Messaging/Force Stop/Clear Cache. I also did the battery pull/SIM card pull and restart to see if perhaps this can be pinned down.
I do however, have the Mobile radios on even though I'm at home with WiFi needed. I did see a thread somewhere else that VZW thinks the texts are being sent on all three radios (?) at the same time.
Today my wife got two different text messages from me about 10 minutes apart. That was correct. However, about 14 minutes later she got the exact same two again, twice but right after each other.
My account does show them as sending four messages at the exact same time long after they were correctly sent.
I was completely stock when it was doing it, no handsent and no astro. I ended up getting rid of the phone when it started sending messages to other people, I would type in the conversation box and hot send and it would randomly send it to one of my contacts, pictures also (thank goodness nothing bad went to people it shouldnt have)
I've had this sorta thing happen to me too dating back to my previous phone too. Sadly I don't know the cause but I do know the solution (until it happens randomly again). Shoot sometimes I will even get multiple texts from the same person when they only sent it once. Regardless, the simple solution is a restart and in cases that doesn't work, remove the battery, let it sit out for a minute or two before replacing it and then allow your phone to reboot. Hopefully this helps you guys!
This has happened to me twice (so far). Both times I rebooted the phone and the problem went away. Unfortunately I have no idea what can be causing it. I do have Astro File Manager and I use Go SMS as my messaging app.
I've also received triplicate messages from non-Thunderbolt users on occasion, so I don't necessarily think it's an issue with this phone.