I've just replaced the rear derailleur and cassette on my bike. I have Shimano Tiagra 9 speed shifters. The cassette is now a 9 speed 11-32 and the derailleur a Sora RD-R3000-GS.
I've set the limits on the derailleur, but I can't get the indexing right. Either, it shifts perfectly going up but won't then drop from the 32 to the 28 ring. Or, it shifts perfectly going down, but won't then rise from the 11 to the 14 ring. I've made as small an adjustment as possible, and yet there doesn't seem to be a happy middle ground.
I've also cleaned the cable / applied bike oil and the mounting point is not bent (following the advice in Why does my rear derailleur's indexing work for either the high or the low gears, but not both?)
What am I missing?