In relation to this patch: D5541
This patch rewrites the Mapping node to support dynamic inputs. The
Max and Min options have been removed. They can be added as Min and
Max Vector Math nodes manually.
The problem is that Min and Max Vector Math Nodes don't really do the job as they should, instead all values are returned as Black.
OK so I dug poked a little tiny bit and wondered what if I flip to first maximum, then minimum, and voila, it works. But how is it possible that works? In any case, the way Blender 2.81.8 updates .blends right now is wrong. It puts Minimum first at 0 0 0, then Maximum at 1 1 1. Some math genius please inquire.