As per faq when a question gets upvoted, I should get +5. When I hover my username, it shows +10 for one of my questions I posted. When I check my point details it shows (rightly) +5 as there is one upvote. Why is this so?
The profile popup tries to show you at least three posts that gained you reputation, starting with any gains for today. If it can't fill this quota, it'll go looking for the entire week, and then the entire month.
In your case, your question was upvoted 6 days ago, then again today, showing the +10.
Try hovering over any of the numbers to get a tooltip* with time breakdown for that rep!
* we really try to put tooltips on any "magic numbers"
Someone probably upvoted the question, then retracted the upvote in the grace period.
The dropdown reputation overview is updated via a websocket, but only for upvotes and accepts, not for un-accepts and un-upvote events. Simply reload the page to get a up-to-date version.