Just fully enchanted a trident (Loyalty III, impaling V, channelling/unbreaking/mending) after spending a lot of time to get one (hardly any drowned are spawning in this version), then lost it immediately when throwing it because I picked up a fish in the hotbar slot I had the Trident in. I tried teleporting to every item to find the Trident item and (/tp @e[type=item,limit=1]) and it was not present anywhere in the world or in my hotbar, it had ceased to exist entirely and I was forced to /give and /enchant myself another one.

EDIT: Just tried again with the new trident I gave myself. It disappeared instantly even though I never picked up an item, Loyalty is broken completely!