RD set screw adjustment?
I've never had problems with an Ultegra rear derailleur before, but today it was having a really hard time going from the third smallest cog to the second smallest in back; on almost every attempt, it failed and made this awful ratchet for at least 4 or 5 spins before I "upshifted" to stop the noise. Is this an issue with the set screws or barrel adjusters, or is it something else entirely? I seem to only get this problem on that specific gear and only when riding, not on the stand.
The upshifts are fine, but the other downshifts are a little clunky as well.