I had cupping on my R1100R with PR2 tires. Started out at around 2-3000 miles and then got worse. It didn't affect the handling other than at parking lot speeds turning you could hear/feel the vibration from the tire. Always ran the recommended air pressure. Bike was loaded up, but riding solo, some higher speed twisties and interstate stuff, but I've never had a bike cup tires like that one did. Before that bike had a Metz on the front and a Dunlop on the back ( the way I bought the bike ) but it never cupped either tire like it did with the PR2. Maybe something to do with dual compound.

It seems from my reading that cupping was a fairly common occurrence on these bikes and I don't know if it was because of the front & rear tire being off set from each other ( not tracking true to each other - directly behind ) or what. I replaced the PR2 with Pireli but never kept the bike long enough to see how they stood up.