Gathering Bloodstone Magic on a new character with both an Experience Booster, and a Celebration booster causes the experience bar to go out of sync. Each Bloodstone Magic orb rewards an amount (with no bonus) but the visual graphic for the xp bar goes up by more than it should. Reloading the zone resyncs the xp bar’s visuals.
Attached is a screenshot of my xp bar, 1 orb away from leveling.