A plunger who bet big bucks at a St. Kitts racebook right before the gates opened, the cycle of processing those wagers through a betting hub in Maine, and a glitch in the Autotote software that connects Aqueduct’s tote system to its closed-circuit TV combined to produce several big odds drops as the races were being run over this past weekend, according to NYRA senior vice-president Bill Nader.

“He stepped in late with big money,” Nader said. “He drops the hammer, and it jolts people.”

Late odds fluctuations have been an on-going problem for years, raising suspicions among horseplayers that someone is betting after the races start. The tracks’ explanation – that betting closes once the gates lock, but there’s a delay in processing wagers from simulcast sites to the on-track pool – met with increased skepticism after the recent Breeders’ Cup “Pick 6 Fix” scandal that exposed flaws in the industry’s computer systems.

NYRA is working to fix the problem by installing new software, effective Dec. 4, that will close betting at simulcast sites when the first horse enters the gate. But last Saturday, the delay in updating odds on TV after they changed on the tote board raised concerns when Harley Quinn, winner of the fifth race, plunged from 7-2 to 2-1 midway in the race.

On Sunday, Nader tracked the day’s betting patterns using a split-screen. He noted that in two races, the price on two horses took a big drop soon after the race began, but there was a 20- to 30-second gap from the time the odds changed on the board to when the changes appeared on TV.

During the sixth race, eventual winner Classic Endeavor plunged from 20-1 to 13-1, caused by a last-minute bet of about $3,000, Nader said.

In the seventh, Personable Pete went from 9-2 to 5-2 in a single flash. That drop took a $15,000 bet, Nader figured. Personable Pete finished fourth.

“They scored big on one bet and took a big hit in the other,” he said.

NYRA traced the late bets on both horses to the betting hub in Lewiston, Maine, which processes the bets from St. Kitts in the West Indies. Nader said St. Kitts attracts “a lot of heavy hitters” because racebooks there pay rebates to big bettors.

The off-shore books can afford the rebates, which reach up to 10 percent of money wagered, because they pay the tracks only about 5 percent of the take for their signal.