In Sol Sanctum, when the elemental stars have been removed, and the bad guys have left, the Wise One tells you that the elemental djinn have been released. However! When you're in Lunpa, talking to Donpa, he tells you that deep inside the cave (which, in fact, is not very deep) there is a creature he fought long ago. But if the elemental djinn had just been unleashed, then how is that possible?

A wizard did it. Or maybe he fought some rare kind of monster that mysteriously resembles a djinn and then died out for unspecified reasons? [Or the game designers just forgot.]

Or maybe not quite all of them were trapped in the first place, when Alchemy was sealed; Donpa's one could have been free the whole time. After all, elemental power wasn't completely sealed either.

yeah, there are 18 of every element, which is more than it shows flying out of the statues, so I guess maybe some of them were already released.

If that were true it might also apply to some of the others in particular. Mia's djinn might have been with the Mercury Clan for generations.

Not to mention Piers had two.

In light of this evidence, it seems to be concluded only some Djiini were sealed.