I confirmed with the Pennsylvania instructions that RK-1 is to be filed with the taxpayer's personal forms in preference to the Federal K-1, no changes there.
I spoke with live support. They confirmed that a federal K-1 requires paper filing, which we know. The "expert" (second-level) agent could not seem to understand that this message is an error, because no K-1 is to be filed when a RK-1 is filed.
That's an hour of my life I won't get back. Hopefully this helps someone else. If you are thinking of purchasing the Pennsylvania product, I would recommend not to.