Hoping someone knowledgeable about Zipp's new 177 hub can help me out.

I received a rear 808 with the new 177 hub & installed a cassette last night. Whenever I install / tighten down a cassette I always grab the inner-most cog with my hands and try to wiggle the cassette up and down the driver body to be sure there is no play (just habitual). When I do this with the 177, the QR cap and entire driver body starts to slide off the axle! I've seen QR end caps that we're easy to tap off with a skewer, but never imagined a QR cap could be slid off by hand (it's not like I was applying 'that' much force...). That being said, I'm not particularly mechanically knowledgeable about hubs / wheels in general. Anyone know if this is this normal? Are the QR end caps just not that secure on this hub?

Thanks.