grey glow on phone display - bug or defect?

[Ashley MLP Fangirl]

ok so my phone (Nokia 7.2) does this weird thing where the display gets a very grey glow. restarting the phone seems to fix it, but I'm wondering if I should return the phone and try to get my money back now, since the device is like a month old. 

 

compare these 2 pictures. both my laptop and phone are on full brightness in both pictures and it was taken with the same camera. the first picture has the grey glow, and the second one was taken after restarting the phone. Spotify is all black normally, just like on my laptop. 

 

 

 

can someone tell me if this is a hardware issue or a bug? and if it is a bug how do I fix it? 

 

I'm feeling pretty massive buyers remorse for buying this and not going with what I know and trust, Apple. if this isn't fixable and it happens again I'm gonna try to get my money back and just buy an iPhone because I don't wanna deal with this...