I don't think the Seinfeld definition really amounts to any more than an opportunity for 'larky' humour.
In common understanding, a delicate genius would be much the same thing as a volatile or unpredictable genius. True genius is obviously quite rare, and most of us don't really understand it.
But it is common knowledge that genius/very high intelligence has a tendency to correlate with mental instability (e.g. van Gogh), and poor social skills (e.g. Newton)
In general I'd call someone a delicate genius if I wanted to highlight the idea of he/her needing to be handled carefully in order to get the best out of their special abilities. I'd call them an unpredictable genius if I wanted to indicate that even with careful handling you still might not get the result you want.
In either case, OP could consider it a (slightly back-handed) compliment. The implication is that OP is normally expected to do exceptionally well, and any lapse from that high standard must be down to the nature of genius, not his stupidity. But in context, it was probably a bit tichy (tongue-in-cheek).