Does it happen to have replacement flipper boards like these:
http://ksarcade.net/new-replacement-universal-flipper-board-type-ii-for-wpc-a-15894-a-17316.html
If so the balls can become magnetized by the sanctum magnet and fire the flippers as it passes up the shooter lane and past the board. You can stop that by flipping the magnets on the flipper board. Hope this helps if it happens to have one of these boards.