So usually I play with Brightness set to Bright (in Video Settings) and Sprint set to Toggle (in Accessibility Settings). But today I started playing (vanilla 1.17-pre3) only to find those settings set to Moody and Hold, respectively.

The issue did not reoccur after fixing the options and restarting Minecraft.

This report may be invalid as I have recently been playing modded Minecraft in a subdirectory of the .minecraft directory. (Options should be separate for different launcher profiles in different directories, but some mods do seem to store stuff in the main directory)