Hello,
I had two false positives on my german event Giratina and Palkia, I guess the event is missing in the database because I got it there.
Giratina: https://www.pokecheck.org/?pk=7770346
Event for Giratina (see Europe): http://serebii.net/events/dex/487.shtml
Palkia: https://www.pokecheck.org/?pk=7770353
Event for Palkia(see Europe): http://serebii.net/events/dex/484.shtml
EDIT: I looked up other Pokemon with this ID in the Pokecheck database, seems every one of them which isn't english/SOM2013 are tagged invalid.
Dialga seems to work normal in all languages, see user tootie a few posts before me