Before Continuing:

• Check you are using the latest version of the mods and its dependencies
• Always include a latest.log if you are crashing
• Remove mod that enhances Minecraft: Optifine, Sodium, others. The issue persists.
• If you are unsure which mod is the culprit.
  Disable all of your mods and enable them 1-2 mods each time to isolate the culprit
• Confirm that there is no existing issue with a similar description submitted in the list of issues.

Version

1.21-FABRIC

Supplementaries Version

Supplementaries 1.21 3.0.0-3.0.5

Moonlight Lib Version

1.21 2.15.6

Issue Detail

Placing books causes them to vanish entirely, disappearing from your hand and never being placed in the world, so they're essentially deleted. This happens on alpha 3.0.0 and 3.0.5 (tried 3.0.6 first but the game crashes when loading world so I downgraded to 3.0.5)