Steps to Reproduce:

1. To activate, a conduit needs to be in the center of a 3×3×3 volume of water (source blocks, flowing water, and/or waterlogged blocks), which itself must be enclosed within an activation frame. The frame is built out of blocks in three 5×5 open squares centred on the conduit, one around each axis. Only prismarine, dark prismarine, prismarine bricks, and sea lantern blocks in the frame contribute to activation. A minimum of 16 blocks are required and produce an effective range of 32 blocks. Prismarine-type slabs (including double slabs), stairs, and walls cannot be used to activate the conduit. Any blocks (of any type) that are not part of the activation frame itself but are in the 5×5×5 outer shell likewise have no effect. Once activated, removing any blocks away from the conduit does not deactivate the conduit.
2. Place some hostile mobs underwater.

Expected Results: When activated, conduits give the "Conduit Power" effect to all players in contact with rain or water, within a spherical range of 32-96 blocks. This effect restores oxygen, gives underwater night vision and increases mining speed by 16.7% (1/6th). Conduits also damage any hostile mobs, like drowned, guardians, and elder guardians, within a range of 8 blocks of the conduit. Conduits can be activated in any biome and at any height or depth.

Observed Results: The conduit power is attained in any condition, but it doesn't do damage to any hostile mobs and the eye remains closed as the Nautilus Shell icon.