Do explain how mass affects gravity in a freefall acceleration.
Ah, but it isn't acceleration they're discussing; it's TV and I'd tend to agree with KenV that WEIGHT*=THRUST
DRAG= Cd 1/2 p V^2 S
Assuming that the parachutist falls in the face-down attitude then Cd will be largely constant.
Therefore since thrust is increased, say doubled with a military load, then TV will be higher but, due to the V variable being squared, nothing like doubled.
*ie mass in a gravitational field.
Re the 'dent in the ice' wrong subscale setting seems to me the most likely explanation.