Randomly inverted screen color

I just downloaded IOS16.6 yesterday. Basically I was laying in bed watching YouTube then all of a sudden the color of my screen inverted. I checked all my settings and they’re normal and I even reset my phone but it was still glitching/inverted, I even let it stay shut off for a minute to see if that would help. I’ve tried everything I could but It wouldn’t go back to normal. The screen flickered the inverted colors for a sec and then just stayed like that literally until I started typing this out. I have no idea if it will happen again or what even caused it to be like that in the first place but it’s back to normal now, thankfully. What causes a phone to do that? How did it do it by itself?