Right brifter (2003 tiagra) is releasing two positions from lowest gear (largest cog) two positions down to 3rd gear. The RD is otherwise well-tuned - note that when it goes down two spots, it is in fact two index positions, not just skipping a gear due to being mistuned. In other words, I can shift gears from 1-3-2-1 all day long, with all the shifts completely smooth. However, it takes more force than normal to do the 1-3 shift than other upshifts.

Any ideas? I'm not sure when this started, simply because I spent 2 years with a bent hanger that prevented me from getting into 1st gear. I discovered this when I bought the Park DAG-2 and straightened the hanger.

Is the brifter just worn out? Clearly this isn't fatal, though I was hoping to sell the bike in question soon.