New Xiaomi MI2- 3.3.15 screen stays on

[kidstretch]

In this 3.3.15 version (and the previous one), i have this problem.
The screen stays on, even though i have the setting to close in 1 minute.
So, i'll just turn it off with the key but then it opens after a while (while reveiving a mail etc) and stays on... This happens a lot of times, many times i've seen the screen on and i closed it manually.

 

[quidje]

This week i was in the car with charger plugged and had the exact same thing. The screen kept coming on. I press power it goes of and comes back on by itself. Sometimes it went off by itself (first fade, then off) only to come up again after a couple of seconds. I was thinking about notifications but there doesn't seem to be a connection.
Mind you this was only on charger.
Same 3.3.15 version on my mi2. I'll try again this afternoon to see.