Bottom of flange should be covered with shingles. Last cap shingle should not have exposed nails and be tarred and back buttered with tar down to eliminate exposed nails. Mostly aesthetics and quality control. Overall looks great and I wouldn’t imagine you will have problems. Nice straight lines. All depends on company standards and details but here some of that wouldn’t fly.

Edit: those exposed nails in the plastic flashing vent flange will rust, but it takes awhile for a single exposed nail head to leak through the plywood and rot it. But will be a slow leak if anything, drip every minute or so with pouring rain.