UtahJock, I'm no mechanical engineer, but oldtimer 66 may have this sussed out. I'm guessing one of the cam locks may not have been correctly engaged. Even so, hard to see how a pallet of 2x4s being lifted straight up only 6" off the ground, could have done this. So I'd also suspect a failed component or weld, as others have mentioned.
Here's my thinking. It's very unlikely that the load could have exceeded the FEL's limit at that height. When you say you were 200 lbs over, what weight are you using as the limit? If it was the 1,122 lbs that JD's website gives in it's basic description, keep in mind that this is at full lift height. At only 6", lift capacity would be much closer to the
breakout force. The breakout force is spec'd at 3,327 lbf at the pivot pin. At 20" forward of the pivot pin, the breakout force is still 2,417 lbf. Even at a carry height of 59", capacity at the pivot pin is still given as 2,125 lbs. Here is the link to the manual:
OMPXX10906
Since your tractor is new this Spring, I'd sure get the dealer involved right away. Your warranty should cover component, weld or assembly or set-up failure, if that was the cause. Another question. Had you detached and reinstalled the FEL between the time of delivery and the mishap? If not, and if one of the cam locks was never engaged and caused the damage, the warranty
may still be worth looking into. JD did not get the good reputation it has without excellent product and warranty support.