Very strange. I had a maple board
RG350 that had almost the exact same crack. At first I thought it was a manufacturing defect. It might have been a bad piece of wood but I think the mystery was somewhat solved when I was standing in the same Sam Ash where I bought it and a guitar fell from the wall with an earth-shattering KErANG! I think the way the trem mounts are set and routed makes for this nasty break if it falls from a decent height.
To end on a positive note the one SA replaced it with was stellar. I very much regret selling it later.