Mine was the same, no reasonable amount of weight or bouncing would reset them. Try using a pry bar to physically move the shackles to the correct angle and see if they stay there. When I did it on mine the shackles actually popped back once I got them started in that direction.
I also had some weight on the springs, I used a jack and stands to lift/support the frame to take some weight off the springs but I needed a little load to get the shackles and suspension assembly to all move smoothly together. Kind of a balancing act where you have some load to get the movement you want but not so much that it cripples you if/when it unloads. There’s probably a better way to do it, but that’s what it took to get mine done.