ok, took the headliner off as far as possible without having to tackle that bs wiring.
So, it seems like that the drains works fine, but somehow if the sunroof is closed and car parked for a long time (multiple weeks) water runs down the pillar and puddles up in the fuseblock.
First of, the closed sunroof and its fitment to the outer roof panels
front
front left
left back
back
back
front
right side closed - no apparent leak
left side closed
this is where the leak seems to be. But how and why the water gets there in the first place
left side
gap between sunroof frame and roof panel - this ridge has to be passed by the water.
from front
btw, looks like there is something missing in these 2 "hinges" - may this cause the leak?