Screen Intermittently goes black

Hi, I'm using a 2014 Macbook pro Retina, I recently had an issue that the machine was stuck in clamshell mode, and would not seen its built in screen. I got it serviced as I was still under warranty. Now I've noticed the screen occasionally flickers black like it's gone to sleep but it's not in sleep mode, and I have to move the screen until it comes back on.

I've reset the NVRAM and used diagnostics mode etc. And it shows nothing, I've also played around my sleep settings and it still happens.

I suspect, the people who serviced the machine did a shoddy job with the cables and they might be caught or something, I'm now out of warranty so I'm asking if anyone has had a similar problem or do you know if it's a software thing? I fear it's hardware.

Mac is barely a year old and I look after it well, I have a 2008 macbook that still runs!I think the hardware has been slowly getting shittier with each release.