A few months ago I was driving along with the roof down whilst it was pissing down with rain quite happily (as you do), staying perfectly dry as i was well above 40mph, until I felt a drip on my right knee. Then another one. And another one. Bugger. Tried opening and closing the window to remake the seal, and also a very brief stop to open and close the door, but nothing worked. The water was getting in and dripping down about halfway down the A-pillar, not a lot but enough to be irritating. Gave up and ignored it and the sun came out so I stopped worrying.
Fast forward to yesterday when the heavens opened big time and the exact same thing happened again. Decided that it was probably worth a bit of investigation this time and ran my hand up the outside on the rubber itself, and into the grooved flap/channel at the top (roadster owners will know what I mean, not sure if it's there on the coupe) and BINGO! My finger slipped straight into a hole in the rubber right at the bottom of the channel, where the fold is.
Bugger
I'm going to try and superglue the whole thing together again tomorrow and see if that works, but failing that it looks like I'll be needing an entire new rubber to replace it. I dare say that's not going to be cheap from Nissan either, but I can't go without my regular roof-down-raining drives, it wouldn't be right!