If the 10 point relay isn't getting stuck on, then a stuck switch isn't the issue. About the only other thing that comes to mind is a cold solder joint and a wire popped off, or there's an open in one side of the parallel circuit path. Could even be the wire popped off the 10pt relay, since those are the only targets that activate it. Does the coil lock on briefly when manually engaged? Should lock on until the 10pt reel steps.

well, just to poke it and see if any more clues can be had, you could jumper a 10 point switch over to the drop target switch line, or vice versa, and see which the problem follows.

If a 10pt switch can activate the G relay like a drop target switch, then the problem lies on the path to the 10 pt relay.

If a drop target switch can score 10 pts (acting like a 10pt switch), then the problem still lies with the 10pt switch path.

Patch the drop target switch line onto that SL-WH-RED line that comes from the 10 pts switches to feed the N relay (or can do it manually by patching one side of a 10pt switch to the 'other' side of a drop target switch, and score immediately).

At least it will tell you if the path to the 10 pt relay is able to work.