Weather effects appear in caves and structures in 1.17.1 worlds loaded in 21w43a

On worlds loaded in 1.17.1, rain and snow appear in structures, caves, and underwater in old chunks when loaded in 21w43a. Chunks generated in 21w43a do not appear to have the issue. The world shown in the last three videos also was not originally created in 1.17.1. The issue does not clear up upon optimizing the world, but placing new blocks will fix the issue for any blocks below. Affected blocks also lack the particles present when rain hits a block.

Reproduce the issue by creating a world in 1.17.1 and loading it up in 21w43a.