Have you checked that cap's ESR? I tell you what I can't tell you how many times the big 470uf or 220uf (with the SE/30/IIsi/IIcx/IIci) axial caps looked great, and in-fact they were bad and causing annoying issues.

With the LC psu's that I fix, some of the pattern failure caps have not even started leaking, but they are still bad.