[Closed] Chain Lift / Chain Skip

I've just upgraded my CDF CX bikes drivetrain and with every complete cycle of the chain under load, the chain lifts slightly (dones't quite settle onto the upper jockey wheel) as it intersects the rear mech. it casuses a rather annoying jolt in the drivetrain and does it regardless of the combination of front/rear sprocket that is used. Is this a sign of a worn chain? I don't have a chain gauge at the moment, but other than the rear mech, it's the only common part...

The Casette, Chain and Chainset are used components, but with seemingly little wear to the cogs/sporackets and the rear mech is new.