The bug

Elder guardians and guardians like to be near the light source when they are idle in the water, even if it is the conduit that will cause them harm.
This causes them to stay close to the conduit when attacked by the conduit.

Steps to reproduce

1. Using the command to set the time to night will make it easier to reproduce.

   /time set night

2. Summon a few guardians or elder guardians in the low light seawater.
3. Found that they will roam freely when idle.
4. Place a light block(level 15) or conduit on the sea floor.
5. Found the guardian or elder guardian began to approach the light source.