Where is the tree located (geographic area) and how's the weather been lately? A few crisp leaves are NBD and the last photo shows a pretty healthy tree overall - is the bark area wet?

Thank you Gardengal !

The acer is in 6b/7а.The last winter was mild. From mid of july till september the days were hot and dry.

There is a sprinkle system running at night.

After peeling some of the black part, it appears to be dry.

The bark is affected 3 quarters around the branch and 20 inches long.

The last photo does cause me some concern. But I think we are looking at mostly drought stress. Sprinkler systems are usually not very efficient at supplying adequate water in the manner that established plants, like trees, require, especially during hot, dry periods in summer. Rather than nightly sprinkling for a few minutes at a time, try an infrequent deep soaking with the hose on at a just a low trickle. You will need to move the hose so that the entire root zone is moistened properly. This type of deep watering takes hours - not minutes - to accomplish properly but gets the water thoroughly down into the root zone where it is most effective, not just at the surface.

The tree seems to have a rather unnatural tilt or lean to it as well. Not sure what that's all about......

Since it will be dropping leaves soon anyway, other than a couple of deep waterings before dormancy, I wouldn't do anything else but monitor it when it starts to leaf out in spring. How well or evenly that happens may indicate if there is anything further than needs to be done.

Thank you again Gardengal !

As always, your comment makes a perfect sense !

Hope my friend will take it easy from now on ,as She really cares for her trees.