I looked at it with a magnifying glass, and it looks like it’s a crack.
It is right at the edge of the brazing joint, so it could just be a separation in the paint.
At this point, I don’t have that much to lose, so I may just build it up and see how it goes.
I don’t think it’s the type of thing that would result in a catastrophic failure.
It just took a little bit of the wind out of my sails.