Drowned will still throw tridents even when the player enters creative mode and they will stay aggroed when the player changes gamemodes, this is like how spiders and enderman used to act on the Xbox360 Edition.
MC-211496
Broken Aggro/Drowned
Resolved
Duplicate
0
Jared Nunes
(Unassigned)
Unconfirmed
(Unassigned)
1.16.4, 1.16.5 Release Candidate 1
Retrieved
This appears to be a duplicate of MC-146524, which hasn't yet been resolved. If you have any additional information to provide regarding this issue, feel free to comment on the parent ticket. If you feel that this issue is affecting you, feel free to vote for the duplicated ticket, to give Mojang a basic idea of how many people are impacted by the problem. Just to further inform you, this will not determine how quickly the bug gets handled or fixed.