I hate to say it, but in my experience, maples exhibiting this behavior are experiencing total root collapse. The tree will continue to push smaller leaves that brown and die until the trunk is completely depleted of energy, then it's over. I lost several shishigashira 1 yr old layers I worked this spring in the manner described above...I suspect a fungal pathogen was introduced when I worked the roots. It took 2-4 weeks once it became apparent they were ill, and despite appropriate care, they all died. I also had a trident years ago that I suspect suffered freeze damage to the roots after it started to grow...it did the same thing for a few weeks then it was over. With this said, the best thing to do is stop any fertilizing and keep the soil just barely moist...damaged roots don't pull much water or ferts from the soil. Morning sun is best, too
One thing for certain if you think its too much water you do not want to give it a misting at all that would just get it more wet . lol Another thing that would help with questions that you have would be to fill out your location in your profile so people could give advice more specific to your USDA zone. When you repotted the tree did you take back the foliage as much as the roots, the reason I asked that if it has a massive canopy (18 yrs. old) and you did a major root prune to fit it in your pot it may not be able to support the leaves with the root system it has left. Its a good practice to remove canopy in equal amount to the roots removed.
