Many of those warnings do not go away. If you have done what it told you to do, then just go ahead and transmit the email. 

I have the same situation, but unable to solve it.

Where you able to solve it, how?

No. I still have the problem. More important, the best response was that the user can't resolve the issue, Intuit is unresponsive, and the only choice is taking a chance of rejection by ignoring the diagnostic as to file attachment or paper filing. NOTHING from Intuit. Does that make any sense at all? It certainly isn't support and merely qualifies for obstruction.

Did I miss something and the IRS is now instituting the death penalty for a rejected return?  Why not try what George suggested and see what happens?  Or you could just keep coming back and complain until the due date has passed.