I opened up a new world in the latest snapshot 21w03a, and noticed that the blocks had gaps between them.
I think I've seen this in another version too, but I can't say for sure.
EDIT: Is a duplicate of MC-1794
Environment
Windows 10, Java Version 8 Update 271(build 1.8.0_271-b09), Nvidia GeForce GTX 1060 3GB
Duplicate of MC-1794