Coral-spot Nectria Canker is caused by Nectria cinnabarina. Hosts Nectria cinnabarina attacks over 90 different genera of woody plants in landscape and forest settings. Common hosts in the landscape include: beech (Fagus), maple (Acer), elm (Ulmus) and honeylocust (Gledistia). Symptoms & Disease...
oak isn't listed. I also question the presence on the deadwood based on the description from the link above. Shouldn't be much sugar in the dead wood, no?
I wasn’t so concerned about the specific species as it just said “common species affected”. I do question the sugar concentration of dead wood. I’d be surprised if there wasn’t any though. It’s unlikely but it fungus may have killed the branch rather than the branch having been cut off by the parent tree for lack of production. But, the dead branches were in shaded areas.