Once it has been fired a Point relay will hold until its Score Reel has advanced to the next digit. Each Score Reel has a normally closed End of Stroke (EOS) switch that should open once the plunger has pulled all the way into the Score Reel solenoid. When the EOS switch opens, it cuts power to the Point relay which can then relax. It's a feedback mechanism so the Point relay and Score Reel need to work together.
In your case one of the 10 point Score Reel EOS switches probably isn't opening, or is shorted some how. Do you have the same problem with both players? If not start by checking the Score Reel of the player that shows the problem.