Appears to be happening only to service center transfer cases .... or cases where the I-140 was filed in one SC and due to the rule change, I-485 was filed in another SC.
My I-485 was transferred from VSC to TSC in March this year and my I-140 had a soft LUD (no message change) on Nov/25. All of my colleagues who also had their I-485 transferred from VSC to TSC are now seeing LUD changes on their I-140, irrespective of whether I-485 has been approved or not.
I'm guessing here, but it could be that USCIS is doing some housecleaning and moving all I-140s to the same SC that currently has the I-485 documentation.
Cheers !!