If you change the award level does the behavior change? If so chances are that the contacts on each player's score reels that indicate which digits are showing need to be cleaned.
If the award level doesn't affect the behavior it may be that the contacts on the Player Control Unit (in red) that advance as each player plays are only working for players 1 and 2.
Cinema High Score (resized).jpg
You can jumper across the contacts on the Player Control Unit to test that theory. For example if you jumper the R-Y (red-yellow) and W-BLU (white-blue) wires together on the left side of the schematic, and the Y-W and Y-B wires together on the right side of the schematic you remove the Player Control Unit from the circuit for player 3. If doing that allows player 3 to get a high score replay you know the problem is with one of those two connections.
/Mark