I have a Ultegra10-equipped road bike with a triple chainring and a 12-25 cassette.
I am having problems with shifting the RD; it skips the 9th largest cog, both down shifting or up shifting. It'll stay in the largest cog, but when I go to a higher gear (smaller cog), it skips the 9th cog and goes to the 8th cog. Then it'll skip between the 8th and the 9th cogs. Very annoying.