Sniffer smells but it doesn't dig blocks

Spawn a sniffer. (Opened Mob Griefing)

It wanders aimlessly and smells. But it doesn't dig any blocks: Coarse Dirt, Dirt, Grass Block, Moss Block, Mud, Muddy Mangrove Roots, Rooted Dirt or Podzol.

I tested in 1.21.2 (See attachments) and 1.21.30.22.