I'd like to pick your collective brains a bit on some weird clutch behaviour I experienced yesterday.

I was taking an advanced riding course yesterday and we were doing some exercises on extremely slow manoeuvring and a gymkhana. So lots of playing with clutch, throttle and rear brake...

After a while I noticed I was getting less and less slack on the clutch handle. I figured it was just the clutch plates heating up and expanding a bit. So I gave it a bit more slack using the screw at the clutch handle. But it just kept tightening up. So much so that in the end I had reached the maximum of slack I could get out of the screw and the clutch plates were not fully engaged with the handle fully out. So I had to resort to the screw at the other end of the clutch cable. After setting that one from its fully out position to about halfway in gave me back my normal clutch handle free play.

Even after a thorough cool down it is currently still in the same position and functioning ok. So it seems to have stabilized.

Anyone have a clue as to what might have happened? And why it happened so suddenly?