Could be a little fungal thing on the Maple, but doesn't look bad.. Just a typical case of "leafsgonnaturnsoonidis" AKA- it's been a long hard growing season and those leaves have damage accumulation.
I agree with the diagnosis of a possible chlorosis on the boxwood. That and some under watering I suspect. Get some low N, organic ferts, feed a little now and heavier in the Spring, might want to get a good micronutrient sublime not to add... Maybe some Iron... If it got WAY too dry, the tree might not make it, but if it is just a nutritional thing, it could pull out of it by next year... If it is root rot or something more serious, well you might be looking for a new Boxwood next year! I hope that is not the case for you, but you learn something new every time you lose a tree!