Possible cause of heavy clutch pedal?

[g650]

Hey guys, I have a new clutch that should be operating fine but has become heavier to use in just 1 year.

I bought my XR6 2 years ago when it had an almost undriveable heavy clutch pedal. Found the firewall cracked and cable worn and fixed up both. Pedal box seemed fine.

Ended up getting the clutch replaced about a year ago, going from a worn heavy duty setup to an Exedy standard.

It was almost too light when replaced before settling into what I would call 'normal' or how I assume it was when new. Drove great for almost a year, but now it's become heavier again.

I've replaced the cable again with no noticeable change. Sprayed lubricant through the bellhousing access box onto the front retainer which helped somewhat, but still heavier than it should be.

Just wondering if anyone has had a similar experience where a brand new standard clutch went from light to heavy over a few months and if there was a reasonable fix or part that needed attention?