I use the Staff of Traveling to gain altitude for the Elytra Dark Plate. In very very rare occasions instead of teleporting me it teleports another player to the target location. I can't really reproduce the error as it's so rare, it happened twice so far in probably twenty or more fully charged staves.
It usually happened when flying at relatively high speed, and the server we're using sometimes has trouble loading chunks (or generating them).

Full Version: 1.10.2-3.0.1.120_beta (as part of the Hermitpack launched through Curse/FTB)