Campagnolo Nuovo Record RD Skipping Issue

[Mapturner]

I had this problem on my bike with a NOS regina chain and 6 speed freewheel. Mine was jumping on the third sprocket which turned out to be off centre between the 2nd and 4th sprockets. My local bike shop removed the sprockets and then refitted them and i was told that it might not of been tightened up properly causing the splined sprocket to shift off centre...