Hmm yes with one 'u-collar' I can see now how it could pivot/scissor closed. Ouch.
Maybe optical illusion, looks like the gap between the 2 tubes isn't uniform? Adding second clamp it wouldnt need to be so tight that tubes couldnt still pivot a bit if needed for insertion. But doesnt look like dealer error-, still think I'd add second clamp.
Im noting the use of the quick links..were those dealer installed? Ive never had luck with them long term-threads gall if high load seen (or me reefing on em).
..edit- with the tubes removed from hitch and the single bolt clamp at opposit end, theres nothing other than friction to keep the ends from closing, unless your finger(s) is between the tubes.