FYI, this happens if you press a number pad key (or a number key) while not having a text input slot active (no blinking curser in it) when in a menu with a text input.
It is activating the targeting/navigating system for controller/keypads where it puts the 'cross hair arrow' mark on intractable items, like the retainer summon bell.
You normally don't see the target arrow due to the open menus in line of sight to the summon bell.
Always 'click' the slot to get a curser before you type to prevent this.
If you get 'stuck' in this mode, just spam ESC to clear out the menus and restore to mouse control.