Summoners War: Chronicles

When i try to restore a particular monster (Hellish blizzard) it won't let me, despite she's not on my team, not in arena defense and i even unnequiped her runes.

The message is the classic “monsters in use cannot be restored" but she's certainly not in use, this doesn't happen if try on Silverfang wich is also an event unit or any other unit for that matter.

I've basically lost a lot of devilmons for the purpouse of trying her out, help.