That was my immediate impression watching this, as well. Something big shifted, maybe cut some hydraulic lines, and a radical nose-up attitude resulted and a stall was the understandable outcome.
MRAP’s aren’t light and if just one rolled back into the tail on takeoff, that is it.
Since the Cargo was 5 mine resitant vehicles, it should be easy for the FAA to determine where they were during the crash and if they shifted. It like 5 “Black Boxes” on board.
On the other hand, if it were rear-heavy, it wouldn’t have gone nose-down after the stall, which it did do. Had it just 10,000 feet more altitude, or maybe less, it could have pulled out of the stall and kept flying.