Been in contact with the Lee support...got the latest primer feed assembly. Installed it, same problem only less so. Primers drop from plastic container that is jiggled every stroke of the press to initiate/maintain/feed. Problem as I see it is the feed and assembly are all the same size and SPP or LRP are not. The primers can lock up with too much weight on them for gravity to overcome.
Additionally, the mechanism to move the primer from the feed location simply is not reliable. The primer can be scooted forward a little or a lot. If you do a stroke that for whatever reason is not a full stroke the primer will be half or part way to dead center of the brass. When you complete the stroke the not-positioned correctly primer jams if you are lucky or is squished half in and half out of the brass, jamming as it tries to load at the next station. In the meantime the next primer in line is not positioned properly either.
I got tired of being unable to complete 50 rounds without a primer jam no matter how exact I was with the push pull stroke on the press. If there is a new assembly, say since June 2019, I would look into it and see if I could get it to work. Decap and priming external to the press is to me a huge negative.