The Spolar does almost (key word, almost) flawless job with the primer. I suspect there is a track alignment issue on the machine in the video. I remember when setting mine up the instructions seemed a bit odd at first that the track would be tilted just slightly. Can't remember which direction, but I must have been very lucky doing mine, as the primers don't hang at the top on mine at all.
I must confess I use Spolar hydraucic also, and on the video the stroke appeared incomplete to my way to thinking, probably to minimize the vibrator motor running?
I will confess that even with the low primer led, I have on two occasions let the track run very low and there is not enough pressure to push the primer into position when you do that. Once I got past doing that, almost 100%.