Nanna's Staff

Staves are really wierd, they seem to both go off of their attack skill and their healing skill; you can only make them hold nothing if you have neither equipped. I do not have a Nanna so I do not know, in your case. If it is new and she doesn't have her weapon on I would say it's probably due to the new healing skill.

EDIT; I checked the old datamine for any new staff images, and yeah, there was one. Since there was no new staff attack ability added, it's almost certainly that, yeah.

That's Restore+. If a staff unit has a weapon that takes priority, if they only have a healing-assist and no weapon then the healing staff sprite is used.