Have you called the nursery where you purchased the tree? They may have advice for you. Planting a tree in the summer, though, seems strange to me. The one time I witnessed the birth of a successful tree, I was a kid. My father planted a maple sapling in Rancho Cordova, California.
Many years later, I drove by the house. The little sapling--which had almost been killed by my father's zinnias its first year--was, oh, maybe 4 to 5 feet across at the trunk!
He planted it early in the spring.
Here in the Bay Area, late fall is a recommended time for planting trees because the winter rain will help them establish roots before the coming dry summer season.
I know that your precipitation patterns are completely different in Utah; that's why I think the nursery might be the best place to go for advice.
Other than those observations, I can only quote Sunset's Western Garden Book:
"The larger maples have extensive fibrous root systems that take water and nutrients from the topsoil. The great canopy of leaves calls for a steady, constant supply of water--not necessarily frequent watering but constantly available water throughout the root zone. Occasional deep watering and periodic feeding will help keep roots deep."
And then, with regard to Autumn Blaze Maple specifically:
"Acer rubrum....Native to low, wet areas of eastern North America. Fairly fast growth to 60 ft. tall, 40 ft. wide (or even larger). Faster growing than A. platanoides or A. pseudoplatanus. Red twigs, branchlets, and buds; quite showy flowers. Dull red fruit. Leaves 2-4 in. long, with three to five lobes, shiny green above, pale beneath; brilliant scarlet fall color in frosty areas. Tolerates most soils. Not at its best in urban pollution....
" 'Autumn Blaze' (A. x freemanii). Dense oval, upright crown, excellent orange-red fall color."
Maybe the roots dried out? Maybe the temps got too hot?
The nursery should know. Let us know, and good luck with the tree.
USDA Zone 9, Sunset Zone 17