This won't generate pages of discussion but might help someone else having a similar issue.
For several years I've installed and removed a thrust bearing in my 650. It does seem to slow the shell plate down and reduce powder spillage when loading .40 S&W, the primary cartridge for which I bought a 650. Following .40 S&W in volume is .223 Remington. I've been trying for a while to build up a stock of .223 but the press has been cranky lately. A lot of cases were tilting as they entered the shellplate. It took a while to figure out just what was going on to cause this because it didn't happen with every case fed but it was more frequent than one of every ten. I may as well have been using my 550 because I spent so much time putting cases back in the feed rails.
Watching the operation very closely and moving the operating lever in ultra slow motion compared to the speed at which I load the .40s, I finally saw that the shellplate was touching the case near the bottom of the ram travel, before the cartridge opening fully presented itself for the cartridge to slip in. It was a timing issue of sorts and it was the cause of the cases tilting.
The thrust bearing was removed and the shellplate adjusted as close as I could without creating excess drag. That allowed the spring loaded ball beneath the shellplate to snap the shellplate in place before the cartridge got to the shellplate by just a hair, but that's all it needed. I have only had the problem with .223, probably because of the very small diameter of the case heads. The bearing works well with .40 S&W cases and helps prevent powder from jumping out of the cases as they lock into the next position.