Light from iPhone 6s+ flickering?

So I'm noticing that when I use my phone for certain things, ie Instagram, some gaming apps, and notes, my phone will do a weird glitchy screen thing. It's actually doing it right now as I type. To be more specific, the lighting sometimes flickers darker then brighter. Kind of like a lightbulb about to burn out. I also sometimes see green blocks for a split second before it goes away.

And no, my auto brightness isn't on.

Just curious if I'm the only one experiencing this.