The flipper scoring points is one of two things, one being fairly straight forward the other a royal pain in the ass. There is likely a PF switch that is gapped too close and the vibratoins from the flippers flipping are causing this switch to close, adding the points. If you can narrow down the amount of points being added each time you should be able to narrow down what switches to check. Failing that you will have to check each switch on the pf. If you can 100% rule out it's none of the switches causing the points, then it's unfortunately EMF running up the switch wiring and causing havoc on the MPU. (it usually causes random pop bumper firings as well) The best way to confirm it's EMF is to have someone physically hold one of the flipper bats in the "Up" position and then quickly press/flick that flipper button. If you have random scoring happening (or pops firing) at this point it's clearly not mechanical vibration causing the issue.
I had this very issue with a clients Mata Hari and it took me a LOT of time to figure this out, and the only solution was to separate the switch harness from the coil harness all the way from the MPU down as far as I could onto the PF. This requires clipping all of the zip ties and physically separating all of the switch wires away from any coil wires as much as possible, then tie each new bundle up and re-fasten to the backbox and PF. (and the further away from each other the better) As crazy as it sounds this solved the problem, and it's an issue that seems to be more frequent these days as there is a a HUGE thread over on pinside with tons of great information and testing surroudning this problem.
Here's a quick vid showing the issue on the Mata Hari;
Hopfeully it's just a mis-adjusted switch.
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