This is most likely a duplicate, but I searched for 10 minutes with several keywords and could not find a glitch like this, so I apologize in advance. While walking though caves, every few blocks a weird flash would come across my screen. I eventually stopped to see what it was, and it was a visual glitch. It seems that the higher your FOV is, the more visible the affected area is (for obvious reasons) Photos showing both normal FOV and Quake Pro FOV are attached.