I just swapped to 20w10a from 20w9a on my hardcore world and the first time I threw my trident at a mob, (phantom) it disappeared of the face of the planet. 

I recreated this by duplicating my backup world and spawned in the same trident, and the same issue occurs. I can throw the trident anywhere and it'll come back. (Loyalty III) But when it hits a mob, it'll disappear.

Is this a bug in the new snapshot? Or is there another issue on my end?

Any help is greatly appreciated