I can't reproduce your issue and I don't remember if anyone else has reported it, so a software update might not fix your screen. Maybe the characteristics of your screen or its controller are different than the standard. Maybe the controller provides some leaking electricity that triggers some red dots of the screen.
Try reproduce it by installing LCD and AMOLED test and turning the brightness down to the lowest setting.
Go into a dark area and you should see a reddish tinge.
I know how to test screens but for your sake I tried that specific app. Absolutely nothing, black is perfectly black. Maybe other users here will also check it but I guess if it were a general issue, not you'd be the only one who reports it.
when i connect other devices to my hotspot, the wifi connection established but the connection to the internet don't.
I do the same in my nexus 4 and everything works properly
I also have a light glow if I set the brightness to minimum and set a black background and look at it in a dark room. It's perfectly black if I set the brightness to max. But you can only see it in a dark room.
I just checked it now and it works properly. Anyway do you have a working mobile data connection on your Z1 Pro? Try to ''forget'' the hotspot connection on your other device, then turn off and on its Wi-Fi, and connect to your hotspot again.
Thank you, I just wanted to make it clear that when the brightness is up or its bright around me the black is black. It's only when the screen is lowest brightness and the surroundings are almost pitch Black I notice it. But thanks again.