Apple Game Center nickname not changeable.

As the title says I am trying to change the Apple Game center nickname for my mother-in-law and it keeps resetting back to what it was when we hit enter. Things we have tried are

rebooting the system

updating and rebooting the system

logging out of Game Center and updating system then rebooting system.

all apps are closed out as well so I am at a loss now. Any help would be appreciated and no I do not need or want the basic of what to do as I have already listed it all above.