The bug

Clicking on a crafting recipe in Spectator mode moves the items to the crafting grid.

How to reproduce

1. Place a redstone block in your first hotbar slot
2. Place a repeating command block with the following command

   /say Testing
   

3. Place an always active chain command block with the following command behind it

   /testfor @p {Inventory:[{Slot:0b,id:"minecraft:redstone_block"}]}
   

4. Place a conditional, always active chain command block with the following command behind it

   /say Redstone block found
   

5. Switch to Spectator mode
6. Click on the redstone dust recipe
   → You will notice that only "Testing" is printed in the chat, but "Redstone block found" is not