I'm almost willing to bet its the glue joint on the riser. Always happens to me, no matter what I do, whenever I build a board bow
All you have to do is make either the belly board thicker to start or add a powerlam and handles will never pop off.
So does it happen at the same part of the draw?
Are you certain it isn't the string running incorrectly in the nock?
If it was the glue chances are it would have blown.
Potentially it could a laminar seperation going on somewhere.
But my first question is the important one!
With red oak in a narrow crowned belly it could just be the chrysals appearing!!!!