What you are experiencing has been very common the past couple years.  It is called Bacterial Blight.  The wet spring was a great contributor. It is not fatal. Sanitation is essential.  Clean up and destroy all leaves as they fall and clean the area completely this fall.  You may  or may not see this occur again next year.  It depends on if you have removed all infected leaves and if the weather conditions promote it.  https://extension.umn.edu/plant-diseases/leaf-spot-diseases-trees-and-shrubs#bacterial-leaf-spots-and-blight-1156513