Definitely a poor brazing job - with the easy ability to gauge brass penetration on this joint, it's hard to imagine how this happened. Built on Monday maybe?

How's the fit of the steerer tube to the fork crown? It certainly looks a bit gauled. If the fit is still good, it should be easily rebrazed. If it is too loose, rebrazing may introduce an alignment problem.

Find either a good framebuilder or a replacement fork (which may be hard to find)

Good luck

-Gary