I have noticed several times my clutch sticking, sometimes badly after wet weather, it is fitted with an oil resistant plate, are these more prone to stiction?
If it is the Siebenrock oil resistant clutch , Have found them to be very grabby ( if that is a word) I don`t think they are available any more.
The Newfren Aramid fibre oil resistant clutches work beautifully although they are a lot more expensive than the BMW oem clutch and had to order from Italy.
It's Siebenrock...
Thats probably it then. Bike is usually garaged, have to put it on centre stand run it in 1st, and jam the back brake. Quite fused together