Drowns disappear and reappear

Drowns with tridents disapear and reappear as they throw tridents at you.

What I expected to happen was...:
Describe what you thought should happen here

What actually happened was...:
when i got out of a boat ( which also disapeared) a drown with tridents kept disapearing while throwing tridents, when i got to higher ground i could see the Drown almost froze in  the water, flickering in and out of the spot he was in.  The boat reapeared when i came back to that spot.

Steps to Reproduce
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