Notebook renaming adds unwanted character stream to title

[Stacey Harmon 1,104]

If I try to rename a notebook, it is adding numbers (appears to be a notebook ID or something) to the end of the notebook name. I'm unable to remove it.

This is in a basic tier account. I haven't tested it in a premium account.

[Stacey Harmon 1,104]

When I went over to legacy Evernote to see if I could correct this, I got the message that "names must be unique". So, that makes sense, but the interface in v10 should give me that message, not just auto-rename my notebook to a unique notebook name. I would prefer to know that the name is already taken. In short, the legacy Evernote workflow/notification system is preferred and more intuitive to users.