Upshot: Federal Review is still flagging 2019 Form 8911 as being "available soon". I ended up calling into support who advised that the support personnel have come to a consensus that the Mac offline version is erroneously flagging the "available soon" error, but that when you e-file, it ought to go through, and supposedly it will be accepted by the IRS.
I've managed to get through the e-file process despite the Federal Review error.
And I was just notified that the IRS has accepted my return.
