Ok, this was actually funny when I figured it out, why it went south. To be clear this is something I cause, not a bug or something odd about NR. The only thing that is at all suspect if how the issue is reported. The log states that there is a failure to read the configuration of the said dashboard node, or nodes with said dashboard, and the visual result is you get an empty dashboard of course.
This is not a case where something is lost, I just clear the slate, so to speak, to start at a known point. There are other ways to recovery, resolve this or similar, but why repair when you can cleanly replace, is the mind set.
But, here is the kicker, I had disabled elements of the dashboard UI. I thought I had only disabled some flows, but when I traced my steps, looking through the incremental saves, I had disabled parts of the UI, no just UI objects, buttons and tables, etc. But tabs/groups. This apparently was sufficient brake the dashboard? Or disabled it to the point it could not load correctly?
