Tridents despawn in trident killer

Bedrock 1.19.63 on XboxOne

All tridents in trident killers on my world despawned. This was in about the last 8 -10 hours.

All was fine when I loggrd off, but on reloading, I found my guardian farm was not working. No guardians were spawning - it had reached mob cap. They were all in the trident killer kill chamber.

On starting the trident killer I saw that the guardians were not being killed. Found that the tridents were gone.

I checked my other trident killers and they also had no tridents.