Crankcase Heat

[Fineline22]

I now believe it is the other way around, something is heating the oil (when riding only - at idle on the stand no issue) to a point where it damages the clutch.

Definately not an expert by any means but a possible idea
Could it be the clutch isnt getting enough oil therfore causing your heat issue

I had a engine with a burnt a clutch
The burnt fibers had blocked the oil galley that feeds the clutch pack