On my survival world chunks doesn't generate. In First world run everything are good. I created this world on 21w16a and in versions 21w16a, 21w17a and 21w18a chunks are bugging.

[edit]: In F3 I see "Waiting for chunk...".

[edit 2]: If i click "save and quick to title" button minecraft freeze on "saving world" and minecraft doesn't use my CPU.

[edit 3]: If i cleared chunks it will load normaly.