It's not *terribly* odd -- the FBI investigations into Kavanaugh previously are unlikely to have dug into his life as far back as the early 1980s.
This doesn't mean that the FBI missed something before, but it's not possible to draw any conclusions from that alone.
Whatever the truth of the matter, it was clear from the outset that most Republicans would have voted for Kavanaugh anyway, and most Democrats against him. When politics gets mixed into what should have been a search for the truth nobody comes out of it looking good.
I might have hoped that Kavanaugh's display at the Ford hearing would have put at least one Republican senator off, but clearly not. Looks to me like Jeff Flake wanted the excuse of one further token investigation to hide his "yes" vote behind. Now the Supreme Court in the US is going to swing so sharply to the right for years if not decades to come, and it will be interesting (understatement) to see what the effects of that will be.