I wish that was the case, it would be easy. Searched the entire platform and nothing, what I saw was it spawn in and then shatter. No loot... About 75% of the time when running this dungeon I don't see a shard (no one in the group does). This was the first time I was able to watch what happened to it.
I just got done with killing the end boss in dread vault, I scooted around to where the shard spawns just before the boss died. I watched it appear then shatter with no one touching it and no loot dropped. It did not fly around or anything, it just appeared and broke.
This has happened 3 times to me on this run, have not seen the issue on any other boss. I don't want to start any rumors but it seems like it might be tied to the TR. Possibly a combo of their abilities or one given ability, I am trying to track it down. It might not be the case though, I think it has something more to do…