A user's Daily Knowledge Goal (the amount of Knowledge Points they need per day to fully prepare for their next milestone, displayed as "Today's Goal" on the Course Dashboard and Path Masthead) is recalculated every time they log in to the course. However, the value of the goal (how many points they need to reach) does not change during the day. 

The Daily Knowledge Goal runs on the timezone of the user's computer, so a user in Illinois will see it change according to Central Time, a user in London will see it change according to GMT+1, and so on. If a user sees their Daily Knowledge Goal change during the middle of their day, they should first confirm that their device is on the correct time zone with the correct date.