Yeah I'm the guy who pm'd when I found your thread researching similar problems... I have every switch you indicated on mine also registering double in switch test, BUT my "mini PF U.L." (potd, top left switch) does as well and also registers/triggers the next switch on the row, the orthanc opto switch (top vuk). You don't have any oddities with that mini pf switch?

I asked about this in the club thread (on page 53 I think), and one guy seemed to indicate the same behaviour with his lotr there, including the "mini PF U.L." switch behaviour, however his did not exhibit the problem when disconnecting the switch connectors at the board and testing with jumpers as you say yours does. That kind of points in two completely different directions... To double check, you removed the switch/row column connectors on the board, and jumpered one pin at a time down the line on the board down those headers per this process? http://www.pinwiki.com/wiki/index.php?title=Sega/Stern_White_Star_Repair#General_Switch_Matrix_Testing

I guess I need to try that here on mine next, but I wondered if the problem may not just be with the Stern switch test itself - I have no problems in game play and from what I can tell none of the switches act up at all during actual play. I could not tell any switches were double registering when a game is started, and switches are manually triggered... I may just drop it until an actual problem is seen in gameplay though.