Does anyone know why my screen flickers green when I unlock my phone?

[nxth]

I have already sent in my device for repair but the engineer said there was no fault so Samsung won't help me any further. 

I even sent a video to the engineer of the fault and they did see it but still said there's no fault.

Basically what happens is when I unlock my phone I get a green flash on the right edge of my phone. 

Troubleshooting fixed my phone for about 3 hours before it started doing it again. 

When I got the phone back from repair it again took about 3 hours before it started playing up again, although this time I am getting white round marks up the right side of my screen.

The reason the engineer said they couldn't find a fault was because they couldn't replicate the issue.

The fault is very temperamental and it is sometimes hard to replicate but it is definitely there.

What do I do now? It's only going to get worse but Samsung won't help 

[Tourbillon De La Vie]

Does it occur in safe mode? If not then it could be some app/software causing it 

https://www.samsung.com/uk/support/mobile-devices/how-to-start-my-galaxy-device-in-safe-mode/

[Axl677]

Thats the blue light filter turning on its fine srry if im wrong

[nxth]

I haven't tried safe mode yet.
But it done it after I got the phone back without setting any of my apps up etc.
its very hard to know when it will happen also.
One day it will happen a lot then the next day it can happen like 2 times.

[nxth]

The green flash is on the right side of the screen and it looks similar to the edge panel.
But now I am also getting white/grey dots flash up when I unlock the phone (on the right side but all up the screen)

[Axl677]

Oh thats not the blue light filter then sorry i couldent help😥😥😢😥😢😥😥