Also, I didn't attend so I don't know if there ever was any call for a "staggered wedge". I have never ever heard about such a formation, but I would assume it is a squad/platoon/company formation and if it exists would look something like this:
I didn't find anything on google or skimming through military manuals, so this is my best guess ^^
Since the formation seems useless to me (no real advantage of any form at all aside from if leaving the rightmost fireteam to hold position and guard while the others proceed through in a wedge column) I assume there was a mixup of squad and platoon marching formation, possibly because of cluttered or breaking comms.