Bingod

This just started to happen after working normally. On upshifts (low to high) the rear shifter now shifts 2 or 3 gears at a time. All the down shifts are good. It is relatively consistent. From the lowest gear one click on the lever upshifts twice, then the next shift is good and then it upshifts 2 or 3 on the next click and then its good down to the smallest cog. On these bad shifts the shifter itself makes an uncharacteristically heavy/loud click and in doing so upshifts multiple gears at once, as opposed to making one click and the chain jumping cogs as one might expect with a bent hanger or with funky indexing. I have cleaned and oiled the shifter mechanism and checked that the cable moves freely in the housing. With the cable disconnected from the rear derailleur and me holding the cable with some tension i can count the 8 clicks both directions, however the upshifts are noticeably lighter and quieter than downshifts. With the cable connected and indexed then i can upshift across the cassette in 5 or six clicks. Any insight would be helpful. Thanks