Sudden change in clutch action

[Fazerider]

Not experiencing any clutch slip, regardless of gear/revs.  Will have to try and find time to take things apart.

Is there a return spring inside the sprocket cover?  If so, perhaps that's broken?

There is, though it's fairly weak... only there to pull the lever back to position. Mine failed last year and I didn't notice any change in the amount of force I had to apply to disengage the clutch.