Hi Jim B… You say that there is no information regarding “please dont ask again” in the manual. Well, when I search the manual for “Please, don’t ask again” I get several hits. To be honest I did not read through them to see if they are related to this particular issue though. Generally, it looks like they are reset by going into various places in preferences.
A couple of suggestions for your consideration:
Maybe hitting one of the “Reset” buttons that are all over the place under “Device Setup” might do something?
Trash your preferences. Not really trashing them but copy them to the desktop then trash and restart Cubase to see if it works. If it does work then decide if it is worth having to reset a bunch of things. If not, then I would just restore them from the desktop.
Like you, I do wish that Steinberg would chime in here to assist. 
Good luck. If this ever gets sorted out please post your findings. Thanks.
Regards 