I seem to have lost a fair bit of oil from Rohloff Hub. All the blurb seems to indicate that this could be normal, but how much leakage is "normal"? Took sprocket off and checked face seal behind, nothing obvious. But seepage seemed to be coming out around the lock ring (the one with the slots for sprocket removal tool), or possible inboard from behind the lock nut on the axle on sprocket side. Intermittent too, maybe depending on axle or hub clock position. Oil been running onto chain big time, occasional pool of oil on floor - maybe 3 or 4 times since last oil change in August. Anyone else had this problem - is it a cause for concern?