After the maintenance and surprise move to open up previously unplayable PSOne and PSP games on the Vita. Someone at Sony has had a hissy fit and revoked the changes, so now if you missed out, you can't download certain games on the Vita. If you got them, then well done, you! Sony on the other hand is missing the point.
Rule one of customer experience, don't give people something and then take it away.
Rule two of customer experience, if you make a mistake explain about it, don't muck about behind the scenes.
Rule three.... see Rule one.
I see no official word from Sony about what's happening here. It can't be a licensing issue, as the games were already there. At best we can hope that someone jumped the gun. At worst, Sony has just shown they can do something that benefits users and has decided to take it away again, cue toys out of prams and a minor shit storm out of what could have been a beautiful thing. But, Sony's good at producing that sort of result, so we're kind of used to it.