Hello, I am developer of this game
(don't sure you are guy from twitter I chat yesterday or not)
Honestly said, we never found this problem before.
As far as I check the NP-6263-7 means some problem about trophy data corrupt.
Some said that it occur because player turnoff or standby vita while it is sync trophy,
Some said that may it because internet connection problem while sync trophy.
So I don't sure what is the cause of the problem.
Because normally the game only responsible for unlock trophy, sync trophy will be done by PSVita.
Here are some thread i found about this error.
There are some solution in there, but don't sure which one can fit with your case.
Such as set date time, rebuild database, reinstall the game, etc.
Please take look, I will also check up for more detail about this issue.