Defective hardware.  One of the Allen bolts had molten metal filling in the Allen Key recess, making it impossible to use.  The replacement part will take three weeks.
Be wary of sitting on it.  The cushion is only supported by a frame, not a solid piece.
Update:  Changed to three stars.  Wayfair sent me new hardware and sitting on it (at least for shorter durations) is no problem. Fabric does show some wrinkle after minimal use.