I now think both causes. Something caught up that scraped in all up and improper spoking. the front wheel is spoked radial with the heads in but the flange is much smaller so it think it would resist that leveraging stress and being a front wheel, it doesn't have the same cyclical pedaling forces.
I don't there is much danger. If/when it fails, the wheel will get loose and wobbly, not much different from a flat tire.
I wonder if Trek has a engineer/designer in charge of wheels. Would their warranty cover it 20 years later for a different owner. sure not.
I have seen broken flanges but not often. Most are from radial spoking just pulling harder than the flange can take or the old sturmey archer aluminum 3 speed shells that were way to thin. With most of the newer boutique wheels, the rims fail far more often because the fewer spokes are under much more tension and the stress is focused on points on the rim farther apart.
Last edited by rickpaulos; 03-29-21 at 10:57 AM.