Not just Triton. I've seen several makes with "Pheasant Tail" syndrome, even the so called unbreakable Hilux!
As Rumpig mentioned, airbag additives are a known offender but a bloke I know had his fairly new Hilux without bags get very sad nearly to the Cape towing a not too weighty camper.
Too much fulcrum effect with the overhang.
On Fraser last year I saw a Navara & a Ranger on separate occasions with the ailment on the back of recovery trucks.$$$$$$$$$$
Steve