To avoid users moving their DHEDGE around and posting after moving it, a snapshot of everyone's DHEDGE balance is taken once a day, and that balance is used as your upvote share.
Your purchase and then subsequent post must have been too recent, before the next snapshot was taken.
I apologize for any confusion, but there has to be a way to keep each DHEDGE from being used more than once per day. So it was either a snapshot, or pay 1000 BEE for staking. We opted for the cheaper option and did the snapshot.
EDIT:
I have added this information to the queue page.
RE: DHEDGE Upvotes and Upvote Queue