Why does my Nokia Lumia 521 screen on 8.1 keep flashing?

[Windows Central Question]

Nokia Lumia 521 screen on 8.1 keeps flashing

Lately I have been noticing that when I open apps or even play music, the screen flashes continuously. It has happened while using Internet Explorer, and with apps that use IE. Help?

Last time it only stopped because I set the phone to lock screen. I don't know why it's doing this. I have an SD card in too, as well.

 

[Corepc]

What lockscteen apps do you have installed?
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[libra89]

Re: Nokia Lumia 521 screen on 8.1 keeps flashing

I made this post. I don't have any lockscreen apps installed. I just pressed the Power/Lock button so that the flashing could stop. This has happened while watching videos, or using a music YouTube app, but it has also happened when I have used IE in general.