Good Morning Leanne, 

Thank you for contacting the U of M Extension Service. 

Here is a link from the U of M Extension Yard and Garden website: 

https://apps.extension.umn.edu/garden/diagnose/plant/annualperennial/sedum/leavesspots.html

Please click on the following link about sedum problems: https://portal.ct.gov/caes/plant-pest-handbook/pphs/sedum-sedum

This information states: 

Leaf spots, Cercospora, Colletotrichum, or Septoria spp.
Leaf spots are very common, typically sharply delimited necrotic areas on plant leaves caused by a wide variety of pathogenic species. Leaf spots usually are favored by wet conditions and may become important if a large number of lesions are present or if they start to coalesce.

Under those conditions, control may also be achieved with the use of fungicides applied as soon as symptoms are visible.

Here is another link about leaf spot diseases of trees and shrubs: https://extension.umn.edu/plant-diseases/leaf-spot-diseases-trees-and-shrubs#bacterial-leaf-spots-and-blight-1156513

With our wet weather, the fungi can grow. It is important to increase the air movement around the plant. Remove heavily damaged leaves. 

Good Luck!