Relates to: MC-278783 MC-278784

The bug

minecraft:sniffer_egg is not present in the Spawn Eggs tab in the Creative inventory. This is despite the fact that they are an item that can be used to spawn mobs. Other non-spawn egg items that spawn mobs are also in this tab (i.e. spawners, trial spawners, creaking hearts), so the exclusion of eggs seems unexpected.

How to fix

Add minecraft:sniffer_egg to the Spawn Eggs tab.