This sounds strangely familiar. On my Milan I have a problem with "stuck" keys, as if no break-code was received. Since the Milan doesn't handle key repeat itself (this is done by the keyboard), I don't get constantly repeated keys. But when this happens to a modifier, then the modifier is "stuck" until I press it again.Similar symptoms, but I think I cannot get rid of it in aranym by pressing Control.
It's not Control but Alt. It is sane again when I press Alt, so it's the same behavior you see. Mainly this happens when I quit XaAES in the shell that called it.
-- Helmut Karlowski