Dell u2515h - Flashing

[IAcKI]

So I was playing rainbow six siege and I have an issue where if I tab out of the game mid load then the textures sometimes don't load properly. This was one of these times.

The game was black and white and flashing. I played a round or so cause it was super weird. I then decided to alt+f4 the game. The flashing continued when at the desktop. No big deal that's happened before will just have to restart. When I reset even the check display no input detected was flashing. So I went into the bios to take off my CPU OC (Only recently done so, was just troubleshooting). No luck. I the turned the monitor off at the wall still no luck. I then switched across to my xbox one. Flashing still occuring. 

What has happened guys?

How can I fix it?

 

Thanks for any help in advance

[IAcKI]

Update  guys. It appears to have just fixed itself.
Computers do baffle me sometimes!