While in riptide mode, you can freely move your trident using hotkeys before colliding with a mob. The game remembers which trident was used, causing it to lose durability a second time when it inflicts damage, even if it's no longer in your hand. However, if you pick up the trident with your cursor before colliding with a mob, it won't lose durability a second time, despite having been used to attack the mob.

Steps to reproduce

1. /give @s minecraft:trident[minecraft:damage=248]

2. /enchant @s minecraft:riptide 3

3. Make sure there is water or rain nearby to use riptide
4. Spawn a few rabbits
   #Increase the size of the rabbits to make it easier to hit them with a spin attack:

   /execute as @e[type=minecraft:rabbit] run attribute @s minecraft:scale base set 16

5. Launch yourself toward a rabbit using the riptide trident
6. Open your inventory and quickly move the trident to your cursor before colliding with a rabbit. If you're too slow, consider lowering the tick rate.

Expected behavior: The riptide trident on your cursor should break when it collides with the rabbit.
Observed behavior: The trident did not lose durability and break upon colliding with the rabbit. Even though the trident didn't lose durability, the rabbit with 3 health was killed, suggesting the trident was used to inflict damage, not the player's fist. If you had moved the trident using hotkeys instead, it would have broken.