Unwanted defoliation :
We had about two weeks of very hot, dry weather, like we can have in the best years in late July early August. The month of May was actually the hottest month in recorded climate since the end of the 19th century.
I kept this maple in too small a pot for too long. It was in full sun in the afternoon and didn't like it. Almost all the leaves were scorched, so I removed them. Ten days later, new leaves pushed out :