Hey Chris,
I saved your pics and inverted them to take a look.
I have seen this type of blow out before.
Typically on board bows, and on the belly side. My impression is that the wood fiber in that area, for some reason, failed in compression. The reason it looks "blown out" is because as the fibers were pushed together, they had nowhere else to go.
Take both hands palms toward you. Put all your fingers tip to tip and push. The lateral movement is what goes on in the bow. The fibers can not push all the way through the core of the bow so the force pushes them outwards and, VIOLA, a blow out. Your brand could have damaged the fibers or it could have just been a bad spot in the grain.
Like I said, I have seen this several times, particularly with Red Oak bows. There always seems to be a nick, ding or bad spot along the grain (you may have to completely break the bow to do an adequate necropsy).
Red Oak, although a good bow wood, can have some problems that never surface until it is stressed a few times. Again, I see it quite a bit in board bows. The little tubes in the wood that carry the tree's food and water up and down the trunk never fill in like in White Oak or Hickory (thats why ya never see Red Oak whiskey barrels, they would leak). You can get grain runs where the wet season and dry season rings just come apart. The branding may have helped this along.
I would like to see a few more pictures to see where along the bow it happened.
Then again... sometimes bows just break. No whys or wherefors. I have all my busted bows mounted on the wall of my shop. A monument to failure if ya will.
Start another or two. I read somewhere that a selfbowyer who gets one shooter out of three he starts is doing really good.
OkKeith