My god yes! I have this exact same problem. Mh apps completely disappear from my app drawer, if I have a shortcut for them on my homescreen it switches to the generic system file icon, and the phone says they "Do not exist" when I try to uninstall, so they also become un-removable short of a factory reset and SD wipe. Also, if you try to connect it to your computer, it will no longer show up as a drive labled MOT; instead it comes up as a Removable Disk and says to insert a disk. You can't even do a soft reset (selecting Factory Reset in the privacy menu) as it gets hung up while unmounting internal storage: it doesn't throw a FC either, and you can't shut the phone down normally since you can't tap the power off option while it's trying to unmount forcing you to have to pull out the battery. The only way to restore the phone is by a hard reset (hold down vol. up and down simultaneously and press the power button). Even after doing that, don't DARE turn off, reboot, or connect the phone to your computer, because it'll all start over again.
After doing all that, Verizon tech support still couldn't figure out what was causing it and said to bring it back to the store and get a new one. I think it has something to do with the phone not re-mounting the SD card properly, because only apps that I moved to the "Media Area" (I'm assuming that's the SD) go missing.
Simply put; right now, it means you need to get a new one it seems.
