It's just the USB plug not going in cleanly and causing a fault in the phones USB circuit. It can garble the USB on any device but with the micro USB plug everythings close together and it's easier to fumble the connection.
The easiest solution is to make sure all power is removed from the phone so the USB chip gets reset. So take out the battery for a few seconds.
This can happen on the PC side of the USB connection too, in which case shut down and turn off/unplug the power for a few seconds so the standby power to the motherboard is shut down.
When everything powers up again, the USB will normally be reset and work as usual.