I think I do know why

wait!  I think I know why. This time around I left the “To accommodate the source data, automatically customize Microsoft Dynamics CRM list values and length of attributes” box unchecked.

I don’t think I did that when I tried my first import.

My guess is here that leaving this unchecked forces MSCRM to actually see if you have pre-existing values and if so, it will match them up.  Otherwise it just brute forces the thing.

Maybe if I have time (code phrase for I’m not going to do it) I will try leaving it checked and see if I can reproduce the previous non-working condition.

But for now, I’m going to happily chug along. Finally!