There was only $35K bet in the entire exacta pool in all combos. When you have that little in a pool plus a lady rider placing the race, it happens. Had more been wagered and a larger field than 8 entries, that combo would not have gotten as much action unless there was a track tip.
Also, in the 6th a 15/1 to the favorite paid $78 w/a $29K pool. So it's pool divided by wagers minus track juice = payout. I'da been bummed too.