Just got a used bike, trying to get some kinks worked out. One of the issues is with the RD brifter (Ultegra 9speed). After downshifting, it won't smoothly upshift: pushing the upshift lever results in both levers moving. A bit of fiddling will set it loose and allow me to upshift; further upshifting is fine until after I downshift again.
Figured I'd ask for advice here before trying to take things apart and messing them up further