Quoted from Kevlar:
In the video you can see me activate the 4 pop bumpers, the first one scores 800 every time, 2nd and 3rd score 100 each correctly, and the 4th scores anything from 100 to over 1000.
The 4th pop bumper is scoring 800 points in the video like the first pop bumper.
A clue is that the two yellow standup targets on the left side each score 700 points so that's probably where the extra score is coming from. You'll need to work out if it's a vibration issue or switch matrix issue. First off, put a piece of paper between the contacts on both of those yellow target switch contacts to stop them activating and see what happens to the pop bumper scores.
The pop bumpers and those yellow targets all have capacitors on them, make sure none of the caps has broken a lead.