Yes, direct sunlight degrades thc much quicker than if it was stored in the dark. Not sure if it degrades into cbn or something else? You'll need to reasearch google for that answer.
idk ive herd if u harvest to late it will degrade in to cbn which yes is the couch potato high, but i would imagine there is a reason they say to dry and cure ur bud in cool dark places so i would go with the 2 answers above me