Originally Posted by braumeister
... and would indicate to me that one of the chips in your phone might have a defective ground which negates its shielding. Nothing to be concerned about apart from the nuisance factor.
Originally Posted by Totoro
Had some random reboots for a while, could also be triggered by changing cell towers in combination with faulty firmware.
Did you try updating it?
I'd say one of the above. Though any shielding issue, bad cap or any number of things, could make the phone sensitive to external noise.