I've got Campagnolo Veloce gear system and I recently changed my worn-out rear cassette to a new one. Since then I've experienced issues when shifting to higher gears. When I shift, the cable moves all the way to its extreme position, or at least skips 3 cogs. Shifting to lower gears works just fine. This issue is likely not related to the pulley/cassette because I can feel the shifter releasing way too much even if the cable is not connected to rear derailleur.
I have done the indexing and H, L and B screw tuning. Do you have any suggestions how to fix this?
EDIT: The chains were also changed at the same time with the cassette.