That happened to me, too. I added a capsule to a bunch of hubs. I thought they had been placed on the HP home page, and was worried that I had filled it up for my followers. However, I was reassured that I hadn't. So your update probably wasn't seen within HP?
So the only other thing I could think of was that Google saw the updated status of my pages and ranked them a little higher for a bit. I never did find a definitive answer for it. But I hope that helps a little.
Do your stats tell you what the traffic sources are?