I took one of those thin rubber rounds used to get extra grip on jar tops to make them easier to open. I cut it to length and placed it inside the cup. No more slide and bounce.
I went over to a friend house, he purchased a piece of lexan plastic you can find at a hobby store used for R/C cars and planes and simply made a cover.
I think you can also use some clear plastic tubing you can find in the plumbing dept and cover it as well
I am new to reloading and this was a PITA until I made the modification.
It is a quirk I cannot believe they did not address.