Tore it apart today. I think I can explain it
The way I aligned the grain made it cup away from the fretboard at around the 5th fret. And it twisted very slightly and pulled away at the headstock.
I think only my big screw clamps could have stopped it but I have been trying to use less pressure so I don't starve the joints hence the spring clamps. I doubt it would happen again as I usually use quartersawn pieces on the edges. This time it was the rift sawn edges that got me.
I could have filled the gaps as the rest of the board was stuck solid. But I would know and it would drive me nuts. The fretboard would not come up with a chisel so I bandsawed it down and sanded the rest it away.
These pictures give you an idea of were the cupping occurred.
As you can see the side gaps were very minimal.
The gap at the nut was a little worse and it bowed away because of the moisture.
The gap at the heal didn't matter as I would have cut it away.
Oh well back were we started...