For anyone who was interested, Avid did confirm the bug I described, and a fix was included in the 10.2 update this past Tuesday:
Sessions saved in Pro Tools 10.0 or 10.1 with unlinked multi-mono plug-ins may open with the wrong plug-ins inserted (PTSW-163664)
In some situations, sessions saved in Pro Tools 10.0 through 10.1 will open incorrectly. Sessions saved with unlinked, multi-mono plug-ins may open with the wrong plug-in on the track Insert. To resolve this issue, option the session in Pro Tools 10.2, re-insert the correct plug-in configuration if necessary, and then save the session.
Whew! ... Onward!
-Dave