Thanks Matt. I tried to post a link to the site, but it was down.
Sorry I failed to mention the red power wire.

There's a note in the install manual that says if you need to shorten
the twisted pair, to cut the pair coming from the shunt, do not cut
the pair that is attached to the indicator. We didn't cut either, but
what difference would it make?

It also mentions routing the twisted pair away from other wire bundles
"if possible". Well, in this install, the indicator is on the
opposite side of the panel from the shunt, and unless we leave it
hanging, the twisted pair has to be routed along the other wire
bundles. There is simply no room or other route available. I would
think that interference problems would be consistent and repeatable.
This appears totally random and either -0.0 or accurate.

Thanks again.
Jim