By any chance, did you rollover your score?
A score rollover is when you max out the score display (in this case 9,999,990) and it rolls over back to 0.
TPA is suppose to keep track beyond the rollover, but sometimes it doesn't and you end up with a 0.
So what is going on here is the first game will post correctly. After the first game you have to back out to the main menu. Then renter the table. It will now record a high score in the leaderboard correctly. You have to back out to the table selection menu then reselect the table every game otherwise the leaderboard doesn't register correctly.