Hi, 

Is this isolated to one branch? Do you see any holes in the branches or oozing? 

We are waiting to consult with our plant pathologist to see what he thinks. There are some leaf scorch diseases and bacterial leaf spot disease but these symptoms don't look quite like any of those. 

Could you send in a photo from farther out and we can see if that helps us narrow anything down.

Look along the base as well - any bumps? chew marks? is it buried too deeply with mulch?

Emily