Have to press button twice to turn it on

[Sorry for my English]

I've got my Meizu M6 for about two weeks now, and I love it. I haven't had any problem [it just froze once] until three or four days ago, when this thing started to happen.

Whenever I try to turn it on, I press the button, the screen flashes once, but does not starts... I have to press the button again.

It doesn't bother me that much, but I don't know if it's a signal of some other problem, or maybe a known bug.
Just to be sure, is there any way to solve this?

Thanks in advance.

Erm , your not supposed to just press the button , your supposed to hold it for about 2 secconds. And just leave it , Hold for 2 secconds and leave (do not press button again)