Propblast, what you describe in your 3rd paragraph above is very plausible.
I have experienced a rearward CofG change in a C206. Took off OK, pax moved some items in flight to parcel rack, no change in a/c performance, as fuel burnt off CofG moved further aft, on arrival in circuit area 2.5hrs later and taking 10 flap, I had elevator control issues (porpoising) removed flap and increased speed, had pax move stuff fwd. Applied flap again and had control issues, elected to land flapless at higher speed, everything ok. After landing, for my own curiosity, I weighed everything and everyone and found at current fuel load, the CofG was "JUST" over the rear limit. We had some bags posted home from where we were.
If a skydiver had turned around, that could place 80kg about 2 feet further aft with a light fuel load ? ? Ive had skydivers turn around, like they were preparing to exit on jump run, whilst on decent to land, ALWAYS tell them to sit down facing backwards for safety reasons in the event of a sudden stop, but rearward CofG change is another very good reason for them to stay seated.