I got some of those MC wire-wound( and 100M) too that often show upwards drift.
Yes, wire-wound resistors do apparently drift up in time. However in this case it is about +70ppm (maximum, taking in the uncertainty of the meter, and could be below +15ppm ) drift over 27 years, or +2.5ppm/year . I can live with that .
I've bought a set of these resistors, new old stock, from 1 Ohm to 1M (x1,x2,x4,x8 values for six decades). I will make the rest of the decades with these - 1, 10, 100 Ohm, 1K (these with a 4-way connection), 100K and 1M. I also have 10M 0.01% 5ppm Caddock as well as a couple of 1% 1G and 100G resistors, so only 100M and 10G are missing at the moment for a full 12 decades range.
Cheers
Alex