Many, including me, have expressed their feelings about the restart problem that the LG G2x and original Optimus 2x have been facing, and after just finally acknowledging this issue, LG says an update will be coming soon to fix it. LG says this issue occurred when your phone was in standby mode, charging, or when the power button is pressed. This means the issue occurred 60% of the time you have your phone. Well the issue has been found, and European phones will be getting this important update this week, and North American phones will be getting the update shortly after.

Source: LG prepares to update Optimus 2X, banishes unexpected reboots to Never Never Land -- Engadget Mobile