Renamed CF Still Visible

We recently renamed one of our custom fields. It happens to be one that we are
all using in RT at a glance as being visible under My Tickets.

When I renamed the field though, it didn’t disappear from the Show Columns list
under Customize “N” Tickets I Own. I had to manually move the new custom field
name over and then delete the old name. Is this an intended function or just a
slight glitch?