I just had the same leaking yesterday on my C2. The bottom sealed nicely (based on the growing puddle I could see) but the top did not. Last night I cleaned the hemet and the top does not look like it is sealing all the way round. This is the second shield on this helmet, could it need adjusting due to differences in shape? I checked the adjusting bolts under the screen retainers and they don't seem to move in a direction that would tighten the top.
What is this "clicking" of the face shield and did the C2 have that too?
The screen was definately not in the "city" position.
There is no such thing as bad weather, only inadequate clothing.