Anyone know why I can't change my PvZ 2 profile name off "User Dave"?

I keep trying to change the profile/display name off "User Dave" so when I load into an adventure level or compete in a tournament my name won't be "User Dave", but I can't change it I can add more characters to the name, and remove the characters I typed in but for some reason I can't delete any of the characters in the "User Dave" name, I can add characters in between the name (example: add a b inside of the name making it so it spells User Dav"B"e) but again I can delete the letter "B" I typed but nothing else, anyone know if i'm doing something wrong here, or if this is a bug, or if there is something I can even do to help my issue... Cause i'm out of ideas... (Please Note: I tried making a new profile to see if the first/main profile was bugged, but I still couldn't do anything with the "User Dave" display name in profile #2).