'Create New Chamber' Visual Glitch

[homchom]

Hello,

Until yesterday, I thought I was the only one experiencing a visual glitch where the Portal 2 Puzzlemaker (the one that opens when you select 'Create New Chamber' in the 'Community Test Chambers' menu) has very noticeable pixelation around some of the textures. It's not related to my resolution, because nothing else in the game has this problem and some things in the Puzzlemaker look fine. Yesterday, my friend told me they were experiencing the same issue. Is this a known bug, and is there any way to fix it? I am on a Windows 10 computer. A screenshot showing the glitch is below. (note that the glitch doesn't appear in screenshots taken with F12)

Screenshot: https://imgur.com/a/rggiajy