During the daytime, drowned will only target the player when in water. When you exit water and surface onto dry land, the drowned mob will stop attacking/targeting you. However, if a drowned is holding a trident, when the player exits the water, the drowned will continue to attack and pursue the player even though it is daytime. Possibly works as intended.

Steps to reproduce:

• Summon a drowned holding a trident and a drowned without one in water. Make sure that it is daytime.

  /summon drowned ~ ~ ~ {HandItems:[{id:"minecraft:trident",count:1},{}]}

  /summon drowned ~ ~ ~

• Enter the water in survival mode and note how both drowned will target you
• Exit the water and note how the drowned without a trident will not target the player anymore while the one with the trident will continually attack the player.