A lot of people choose to grind nodes down instead of waiting for the refresh(this is called rabbiting). So this score is very possible. It is also a bad strategy if you want to win. Hit all the nodes every 8 hours and you will quickly catch up to the guy/gal in first
There’s 2600 base points 6500 / 2600 = 2.5 = 1 + 5/6 + 4/6. So someone decided to do three full clears (that doesn’t make much sense with 8-hr refreshes but it’s certainly possible).