I'm no expert on light transitioning glasses but my mother as well as a few of my friends wear them and they do not transition in the blink of an eye. They take a few seconds to transition from light to dark or vice versa depending on the light conditions but in no way does this happen rapidly. It leads me to believe that this aspect of the glasses did not have any affect on him not seeing the beacon. However it could have been the glasses possibly being blurry or the frames being in the way or maybe the GPS screen or some other light source was causing the glasses to be in a darkened state. I have been out many times fevourishly looking for a bouy that I knew was there and just not seeing it till the last second. (I don't wear glasses and have perfect vision). Sometimes being on the water in the night can play tricks with your eyes and mind. I think that is the more likely answer then the distant slight blink of a marker rapidly causing his glasses to shift from light to dark and then back to light again in a fraction of a second. Just my two cents.