DISCLAIMER: I am not sure if this is a bug. But blocks in game, past a certain distance(two chunks or so, I believe), show their outline, as if they were selected. I have not tested very many versions, but it appears to affect all installations so far(1.16, 1.12.2). Unfortunately, I have no other computers to replicate this on, and am unable to determine if this is an in-game rendering error, or an error with my PC, or anything else. The glitch is especially apparent on superflat worlds, where flying up reveals a moiré pattern of outlines. It also appears to affect clouds, though not as noticeably.