Originally Posted by
ThermionicScott
If you were using a 7-speed cassette and spacer and are now trying to shift all the way across an 8-speed cassette, it's possible that the RD hanger was always slightly bent and the accumulated error didn't manifest as a problem until now.
After some cleaning, laying the hanger on a flat surface and giving it a couple whacks just in case, and putting everything back on, it seems to hit everything consistently except the smallest cog, which it will shift to, but slowly. However it still sounds like it needs to be trimmed out a bit on the largest ones. It does hit the megarange one fine, though.