Arrows use the "damage" field as a multiplier to calculate their actual dealt damage. Tridents also have this field, but it seems to have no effect - they always do 4 hearts of damage.
To reproduce, set up a repeating command block with:
/execute as @e[type=trident] run data merge entity @s {damage:0d} (or any other damage amount)
Now throw tridents at mobs. The trident will still deal 4 hearts.
Thank you for your report!
We're tracking this issue in MC-136514, so this ticket is being resolved and linked as a duplicate.
That ticket has already been resolved as working as intended, which means this is not considered a bug and won't be fixed. Please do not leave a comment on the linked ticket.
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