If that second pic shows full stroke of the powder bar, it's WaaaaY out of adjustment. It won't even dump powder with that stroke.
Use the powder station/funnel to flair your cases, then use the hole you presently have your expander in for a powder sensor die. Then you won't need that fancy light to check each case for powder level.
Use that 650 the way it was meant to be used. Station 1, size/deprime. Station 2, reprime, flair and dump powder. Station 3 to mount the powder check die. Station 4 to seat bullets. Station 5 to crimp.
As for the powder bar 'STICKING", It isn't "sticking, it's not meant to return by itself. It's made to be case activated to it's complete forward dump position while at the same time belling the case mouth,(handgun). The linkage is there to return it to the powder pick up position, or all-the-way-back. It's adjusted by means of the wing-nut on the bottom, which tensions the spring to compress a bit when the bar is back all the way.
Should still work fine the way you are doing it so long as your powder die is screwed down far enough to fully actuate the primer slide. As far as yours not returning without the help of a failsafe rod, my measure has 2 springs that wrap around the hopper base and the metal piece in the end of the powder bar. Your linkage looks a bit different though so maybe they have done something to change that.
Why are you giving advise on a 650, when yours is a 550? They're different, just how different, I'm not sure. That's why I'll never give advice on a 550, I DON'T OWN ONE! There's no primer slide on a 650!