Q.acer x orientalla minorient
I have an Acer x orientalla minorient, which has been in for about 6 weeks. It has started to get brown shadows growing out from the leaves. Please, can you help?

Unfortunately, the tree is susceptible to many of the infections and pests that attack other maples. These, along with several environmental factors, can cause dieback and even blackened leaves and branches.
https://www.gardeningknowhow.com/ornamental/trees/japanese-maple/japanese-maple-problems.htm