Phone works but sometimes the screen stays black

[AC Question]

Greetings,

I have a Oneplus One and the screen was replaced.
After that when I boot the phone, everything works like a charm, but after a few "turn on and offs" the screen doesn't turn on. The phone is still working, can receive suff, makes sounds and vibrates, but the screen is black, and sometimes after many tries the screen magically works.
I noticed with the lights off that when the screen is black/not working it has a dim light at the bottom but can't see anything beside that.
If I press power for X seconds the phone reboots and the screen works again.

Any idea what the problem is? Is it the new screen?

Thank you in advance.