I'm not sure if this is just a corroded clutch cable but around every one in 5 clutch depressions results in one feeling like the cable sheeth is rubbing internally..it's very odd as it doesn't do it on every depression and maybe more often when I'm pulling away in 1st or 2nd gear..I haven't had a slipper clutch before so is this just what they feel like ? Or is something else going on ? Although it feels like a corroded cable I just don't think it is due to it being so intermittent.
Could be the slipper but worth checking the cable especially at the perch where it goes through the adjuster and at the other end also at the adjuster nut near the engine casing.
Mine doe the same, the dealer mechanic said he thought there was something wrong with the clutch on the 500 mile service but he didn't have time to check it properly (even though they charged £140 for essentially an oil change) Anyway 2 years and 8000 mile later it still does itbut the clutch is fine