Originally Posted by
Bob Dopolina
You've got it.
You need to tighten down the bolt that threads into the braze-on and attaches the shifter to the frame. Should take all of 30 seconds.
Since they are Campy shifters, plan on tightening this bolt fairly often. These thing have a long-term reputation for losing their adjustment and allowing the "ghost shifting" you are experiencing.
I had a set of Record friction shifters on one bike years ago and had to retighten them about every three weeks to prevent unwanted shifts. I replaced them with Sun Tour Cyclone shifters and the problem never came back.