Additional image.

It looks like water stress - no enough. It's hard to see clearly - is it in a container or in the ground? You cannot rely on just rain water during summer to address the water needs of a newly planted tree. How often has it received water? And where are you located?

Yes: physiological leaf burn due to too much hot, dry air, minerals in the irrigation water it doesn't like, things like that. The lace-leaf kinds can be more susceptible to environmental damage than other Japanese maples because of the dissection of the leaves into slender sections.