The only explanation I have is that WSUS Offline was updated at some point in November when it was released, without making a new download run afterwards. Thus the old revisions of KB4474419 downloaded by an older WSUS Offline version are still there and will be installed (because the client part doesn't explicitely exclude them).
To fix this, making a new download run should be enough. However, since MS made some changes to the catalog file in December 2019*, it's possible that the old revisions are not deleted. I'm don't know because I have disabled downloads for WSUS Offline on my systems because of this change.
*) See viewtopic.php?f=3&t=9954.
Regarding the nag screen I have no idea.
Regards
Dalai