A colleague was in PVG during that event and told me the MD11 rotated very late almost at the end of the runway and barely made it into the air-app 10ft.
Cargo shifting unlikely? I arrived once in Europe coming from PVG with all floor locks not up, my good luck was that the aft lower comp was completely full and the cargo only shifted a few cm, but banged itself up in the process of doing so. So I do not rule that out coming from these parts of the world.
Flying the 11 I have to say it is a challenge and needs excellent maintenance and highly proficient crews, both I would raise to question, considering the creative ways of the operator (Z Reg, British Comp etc....)