The bug

Starting with 21w39a the version.json file inside the client and server JAR has an incorrect id value:

{
    "id": "Minecraft.Server / f7d695aa1ba843f2aa0cbc2ece6aea49",
    "name": "21w39a",
    "release_target": "1.18",
...

Instead of being the game version ID, e.g. 21w39a, it appears to be an internal product name containing an internal (Git?) revision ID.

This has an effect on all parts of the game using the version ID, such as:

• "Minecraft Version ID" in crash reports
• Name of generated profiling results ZIP file