Don't spend too much time worrying about that seam, nothing unusual about it at all. The wood in the transom should stop well below the seam and is glassed in and sealed while the boats being layed up in the mold, a leaky seam should have no effect on it what so ever. Unless you have an outboard or I/O, then the wood sometimes runs higher than the seam. Hell, a jet boat doesn't even need wood in the transom, there's nothing to be gained by it except for somewhere to hang stuff. It's not structural.