Join Date:Joined: Jan 2011
I have had this problem with both stock ROM and CM10.x (2-touch) when my battery is in the 20-30% range. 50% is indeed a bit high for the NT to act up.
You might want to look into the battery calibration apps (I myself have not used them). Some of these apps suggest the optional step of letting the battery completely discharge after a calibration, but personally I would skip that optional step as there have been reports of difficulty in recharging NTs that are completely discharged.