On extraction I am getting warnings like this:

% feedback find
Feedback #28: Label "vccd2" attached to more than one unconnected node: m3_n800_633842#
% feedback find
Feedback #29: Label "vccd2" attached to more than one unconnected node: m3_n800_643842#
% feedback find
Feedback #30: Label "io_analog[6]" attached to more than one unconnected node: m3_175894_701300#
% feedback find
Feedback #31: Label "io_analog[6]" attached to more than one unconnected node: m3_165594_701300#
% feedback find

Some are from nodes in test harness I do not use, but some are from nets I do use. Should I be concerned?

These look like places on the analog wrapper where there were two wires connecting to the pad from either side, and so in the wrapper frame these end up being two separate pins with the same name. Since the wrapper is taken out of context of the full chip, magic just sees this as two different nets with the same name and flags it with a warning (which it then unhelpfully calls a "fatal error", which is something I need to deal with some time).