Last fall, I noted (and others on GW also) that a lot of local oaks, mostly in the red group, but primarily Pin (Q. palustris) and Northern Red (Q. rubra) were looking "bighted" with blotchy brown spots that eventually turned whole leaves brown and they fell. Oddly, Scarlet Oak, Q. coccinea, seemed relatively unaffected despite being closely related to the 2 other species.

I was initially concerned about a big Bacterial Leaf Scorch outbreak. However, I think it might have been Taphrina caerulescens, or Oak Leaf Blister. A relatively minor disease that is worst after a wet, cool spring (which we had last year, this year as well it appears).

Does this make sense and match what others have seen?

Here is a link that might be useful: Oak Leaf Blister