What I am trying to say is the behavior changed from a working to
non-working state without my having changed nx-libs on this end, I only changed them after things broke.
Huh, that would be weird. nx-libs changed in the nightly repository on Dec 21, so that sounds close enough to the breakage date.
If you would have updated on Dec 19 exactly, you would have run into the upgrade issue that was brought up on the -dev mailing list a day later. Given that the repository was in an inconsistent state back then, upgrading wouldn't have worked in the first place.
Mihai