When in Creative Mode, placing the block 'Sponge' will cause it to disappear from your hand even though you are in Creative.

How to reproduce:

Go into Creative mode

Get the block named 'Sponge'

Place it down

For more info:

The bug happened on a Multiplayer creative world server.

The sponge was being placed on sandstone

The biome was 'desert'

The world was using the 'Redstone ready' world generation