mixing Shimano and Campagnolo shouldn't work but it does

I have to rebuild my rear wheel which has Shimano-compatible hub and 10-speed cassette. It's a hodgepodge drivetrain: 105 10-speed shifters, Ultegra front derailleur, and Sora rear derailleur. I grabbed a spare wheel with Campagnolo hub and Miche Campagnolo-compatible 10-speed cassette. It works! I know why it shouldn't work. I don't know why it does. I know the "centeron" feature adds slop in deliberately, so maybe that's it? Some shifts are delayed, and some shifts need a little nudging afterward, but that's how it's been with my purely Shimano drivetrains, so this is no worse.