I have noticed the same thing, there is a gap around the nose of the Cosmos that light can peak in, versus the Vive which had none. I don't mind it so much because like Tom I also use it to peak at my KB or general surroundings. I don't wear glasses though.
I remember reading in the Cosmos description that it fits better around glasses, so I imagine that's the cause. I don't know if that part is modular but maybe have two different sizes for w/ glasses or w/o.