Answer: It sounds to me as though the tree is expending its energy in sucker growth instead of top growth. I would cut off the suckers to redirect the energy and then give it a few months to recover from whatever is causing this strange behavior. If it budded out and then stalled and then began producing suckers, it could be that the top of the tree was damaged this past winter, or from a late frost this past spring. I think it will take some time to recover and then you should see normal leafing.
Best wishes with your autumn blaze!
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