Z3 randomnly shutting off

Member

The last couple of weeks my Z3 will randomnly shut off for no reason. Usually the battery is under 40% when this happens.  Then it takes a time or two of hitting the power button before I can get it to turn back on and the other day I got a reboot screen or something that popped up and I didn't know what it was. 

Who I have the same questioned this topic