I have yet to get my hands on a Droid X, but since I've been sent to the back of the line I've been doing alot of forums reading. This sounds like a problem that could be caused by enabling the smart profile for the phone. After it's been enabled if your phone has a problem the only way I've read to fix it is to do a factory reset. Once you've done the factory reset I wouldn't use this smart profile until it's been figured out. According to the motorola forums it's been reported.
Here's a link to the other forums to check it out.
I got an LG Env Touch in January one for me and one for my daughter. I live in Myrtle Beach,SC and she lives in Asheville,NC but has a SC # under my plan. The phone was great, just loved it, when all of a sudden one day when it would ring it would do so for a few seconds and go silent and if you were not sitting there to hear this you would not know you had a missed call or voice mail til you got the alert. I have had 2 certified pre-owned phones and today I just received a brand new one. I only transferred my contacts, put my SD card in, texted my daughter to call me, IT DID THE SAME THING, all of them did. I even let the tech listen to it when she shipped me the 2nd one., so I know I'm not crazy. Then some times I would be sitting right beside it on my end table, never hear anything. I got the new phone today, because I called in on Monday to tell them as much as I pay for my service they needed to send me a new one. But I am so sick of this phone. They need to do something Verizon is getting a lot of complaints on this phone.
Before I registered on here I found someone on here from Sept 2010 that was having the same problem. Then I read on here about the white screens, black screens and having to take the battery out to reset it. I would be texting or just be in my texts that I had received erasing some,etc. and it would flip back to all the messages I had in there in January but the words themselves would not be there. I would have to power off/on.
So anyone out there having the same problem I need an answer... because I am really ticked off. Of course when you go to the store the phone doesn't act up what gives there !!!!!
H E L P !!!!!!!!!!!!!!!!