Items held by drowned are added in the offhand and swapped in the mainhand

Trident wielding drowned will sometimes change their tridents to a fishing rod. Sometimes they will have a nautilus shell in their offhand even though they don't have one before. The drowned will still throw tridents even if it's holding a fishing rod.

Observed Results
Drowned changes trident to fishing rod and gains a nautilus shell in the offhand

Expected Results
Drowned should not change the trident to a fishing rod and not gain a nautilus shell in their offhand

Note: You will notice how the drowned throws a trident with a fishing rod.