I know that qfbclassno() has some troubles, so you might be interested in a small list of discriminants that I have encountered, where the class numbers get computed incorrectly:
D -837969395 -1902713339 -4059602867 -8329227739 -16654815979 -16915749483
For these discriminants, the value of qfbclassno() differs from quadclassunit().