I have just been out to check mine for you.
My sun roof has NOT been opened after about late September of 2020.
So, this is what I have seen.
The “Net” of the sun roof feels fine to me.
There was a couple of drops of water on the plastic frame that secures the net.
When I opened the sun roof to the first setting, there was a number of water beads on the black under side of the leading edge strip just below the front edge of the glass.
I wiped this away with a single sheet of kitchen paper towel.
The car is parked on the slightly sloping down drive way all of the time.
Therefore it is offered NO protection from the winter elements at all.
I was not concerned about what I have just witnessed to be totally honest.
If there is a LOT of water sitting in the frame of the sun roof, this COULD suggest that one of the Sun Roof drain tubes are blocked.
Open the sun roof fully and pop your head out over the lip of the head linings and see it the sun roof surround is flooded with water.
There will be water present of course, but you feel the level is to high, you could consider having it checked.
There should not be an excess of water swishing around up there !.
Remember, my sun roof has not been opened for 4 months, so it has had plenty of time to fill up considering the amount of rain we have had recently !.