I got stuck trying to enter that Hebra mountain shrine too, I figured it was a tiny entrance or something on the north side, just as some of you guys did. Eventually I gave up and kept exploring the area, and it was when I met the shield surfing champion woman that figured it out. She deliberately mentions the large stone door when describing the shield surfing course. Really wish the shrine itself didn't get picked up by the sensor when it's so far from the actual puzzle to access it though.
Yup wasted 3 hours on this just looking around the damn cliff wall until finally GameFAQsing it
It'll show up on your map after you beat the final boss.
Oh shit! Didn't notice. Thanks!
EDIT: 34.82% lol. Seriously? What is it counting?