This is unsurprising given the ALT key is used to bring the menus up. So ALT+T brings up the 'Terminal' menu, and ALT+V brings up the 'view' menu. So in effect you have ALT+T assigned to two things. Perhaps gnome-terminal should realise this and either refuse to let you make the configuration change, or use a different key to bring up the menus.
This is unsurprising given the ALT key is used to bring the menus up. So ALT+T brings up the 'Terminal' menu, and ALT+V brings up the 'view' menu. So in effect you have ALT+T assigned to two things. Perhaps gnome-terminal should realise this and either refuse to let you make the configuration change, or use a different key to bring up the menus.