Phone lock issue

[nycxhobbes]

Ok guys I searched for a bit and didn't see this anywhere but if there is a thread on it I apologize in advance. I am on my second touch pro right now (first one fell in a huge puddle) but i noticed that every once in a while, although I lock the screen using the long end button press (i set it that way) the start button on the top of screen can still be opened. It happens occasionally and mainly just annoys me but I was wondering if anyone else had this issue and if there is a fix for it?