Language file errors sometimes show when I launch Minecraft

Since the 1.17.34 update I get the attached errors sometimes when I launch Minecraft. This happens on both of my PCs.

Steps to reproduce

1. Turn on content log file and content log GUI.
2. Disable any non-vanilla packs in global resources.
3. Close Minecraft.
4. Reopen Minecraft.

Expected result

No errors on startup.

Observed result

Exactly 80 "Invalid lang file format" errors.
Language errors on load.mp4
Startup Errors 1.17.34.txt