This is very unusual.
Obviously, what changes when the Island goes home? The lock pin coil. (scratches head...) No, that can't be it...
This could be a questionable connection on the big square chip on the CPU board. Push it firmly into it's socket.
At this point I would put in a Kahr circuit board. For $29 plus shipping it's a easy way to test to make sure that the problem is or is not related to poor +5v power.
If the problem never happens when the Kahr board is installed, you have something dropping the +5v and you can start going down the recommended fixes, and when you've gotten the +5v circuit fixed you can pull the Kahr board.
If it still happens when the Kahr board is installed, you've got a much more difficult problem, and you'll have to observe very closely exactly what is happening when the game resets.
I've had wires that rubbed through the insulation on metal parts do this... intermittently.
If the darned thing would just break consistently, like EVERY time the island lock pin releases, you'd be able to fix this. It's a whole lot easier to fix it if it stays broke.
Keep working at this, observe carefully, and let us know if you spot something that would lead towards the machine being consistently broken.
Don't give up... this might take a while to figure out!