Until today, I thought I was the only one experiencing this visual glitch (screenshot below) where the Portal 2 Puzzlemaker has pixelated edges and shadows. Today, my friend told me that they are experiencing the same issue. Is this a known bug, and is there any way to fix it? Thanks in advance. (note that the glitch doesn't appear in screenshots taken with F12)

https://imgur.com/a/rggiajy