Dan, what I meant was a second look at the pics shows absolutely no sign of brazing, and red paint is on the crown where it joins the column.
I see what you mean, Keith, there definitely isn't any braze below the crown race seat and bearing race.
However, I think the crown race seat, which was cast into the top of the crown, has broken away with the steerer from the main crown casting itself.
There are signs of braze on the steerer at the top of the crown race seat, above the bearing race, but none below in the body of the crown or on the steerer tube.
So I would suggest that the braze only penetrated approximately 5mm down into the top of the joint (the easily heated thin section), leaving only a 0.5mm thickness of cast crown material (26.4mm OD seat - 25.4mm OD steerer/2) just below the bearing race to support all the fork loads. This can be seen as the thin grey/black line around the inside edge of the steerer hole in the crown. Correctly fabricated, this section would normally have a wall thickness of around 2.8mm including, as it should, the wall thickness of the heavily butted steerer tube.
The untouched red paint on the upper surface of the crown would also suggest that the post-paint prep work on the fork was poor, too. The resulting small gap between the top surface of the crown and the lower surface of the bearing race would only have made the situation worse. The bearing race needs to be pressed firmly down onto a flat square machined surface to run safely and freely.
All the best,
Pause, take a breath and ask yourself: "What would Rastamouse