Newbie here so apologies if this has been asked before.
I passed through airport security twice today (Boston, MA and Amsterdam) and the TP went through the scanner with my carry-on luggage.
I got the TP out of it's sleeve some five hours later and there was an almost perfect circle in the centre of the screen about 1 inch in diameter. It looked like somone had drawn the circle with a soft black pencil. I rubbed it and nothing happened. I turned it on and the HP logo appeared in the same place as the ring and the 'pencil' ring vanished.
I assume the 'mark' was inside the TP and was wondering if this has happened to anyone else.