While using tridents in a few trident killer systems, (tridents thrown on glass block) after a seemingly random amount of time, all of the tridents in the systems disappear (all 50). It does not seem to be a rendering issue, and this is also a repeating issue. (if it matters, the tridents are above an under sea temple)  as a note, the tridents were thown between the extended pistons. (see photo below)