Does Imprisonment work on an Eidolon?

[dracklor]

Would Imprisonment work on an Eidolon, or would it just reform on its home plane as it was moved too far from the Summoner?

My Mythic Campaign had the players go up against a Thanatotic Titan from Bestiary 2.

They are level 12 Mythic 3, and it was fighting a Yamaraj Psychopomp from Bestiary 4 at the time.

They defeated it aiding the Yamaraj and gaining its aid for their quest, but the Titan got off an Imprisonment spell before death.

I decided to hit the Summoner's Eidolon with it, thus ending the session with them earning enough XP to hit level 13 and gaining a Mythic tier for defeating an epic for.

Now once they planeshift back to their base will the Eidolon despawn and reform, or will they have to find someone to cast Freedom on that battlefield to reacquire their ally's minion?

[Melkiador]

Imprisonment doesn’t seem to protect the eidolon from being banished by its various mechanics. But it would still be under the effects of the spell. So, when you resummon it, it will basically have temporal stasis cast on it.