The Bug:

Attempting to place glowstone into a respawn anchor in spawn protection causes a desync.

Steps to Reproduce:

• Start a server and join it.
• Give operator permissions to yourself.
• Set the world spawn to your current location.
• Place down a respawn anchor.
• Obtain a block of glowstone.
• Switch into survival mode.
• Remove your operator permissions.
• Give operator permissions to any person other than yourself.
• Attempt to place the glowstone into the respawn anchor. (right-click).
  →  Notice how the glowstone disappears from your inventory.
• Click on the space in your inventory where the glowstone was previously.
  →  Notice how the glowstone is back in your inventory.

Information:

When attempting to place glowstone into a respawn anchor in spawn protection, the action succeeds client-side but fails server-side, causing a desync.