Yeah, I had an old Vari-XII 3-9 that was the same way - held zero and worked great, as well as a 2-7 and 6-18 from that era that are still chugging along. The newer Leupolds seem to be the scopes having the most issues. I think that's why others are having trouble wrapping their minds around the issues, as they seem to be the guys who have a bunch of old Leupolds that continue to work.
Just this season I saw two Leupolds made within the last few years with large zero shifts and not be able to rezero (adjustments went completely wonky), and another which saw a massive zero shift but adjusted back on target and was able to finish the hunt (the last one was on my own rifle).
