Mine's the same.
I think the OE clutch springs are a bit marginal, but the only after-market ones I could find were about twice the stiffness and made riding in London traffic almost impossible.
OE on the right: thinner material and more turns.
Even if I had had the hand strength to operate the lever easily I don't suppose the clutch basket would have taken the strain for long.
As for what's going on in the clutch, I guess you're experiencing stiction. Once it starts slipping it tends to continue, back off for a second and the plates and friction material can lock back together, re-apply power and the surfaces stay locked because the heat you put into the surfaces the first time has thinned the oil enough.
The cable may be slightly slacker after enthusiastic use of the bike because, if you get the clutch hot enough, thermal expansion of the stack of plates (plus pushrod) is more than that of the engine casings.