I throw a Trident into trident killer, use for a few minutes to collect necessary items, then leave the area (far enough for chunk to unload) and the thrown triden despawns prior to my return.  I have tried naming the trident and name tagging them to no avail.  After chuck unloads all thrown tridents despawn rendering my killers completely useless and requiring I go back out to an ocean and spend an hour hunting for more tridents to replace them all only for it to happen again the next use.

Area is in the Overworld, approx 128 blocks (y axis) fully enclosed 2x2 kill chamber. Made of stone bricks and Deepslate blocks using tinted glass as viewing window