I don't pretend to have the answers but some things are obvious. Since SSSC M39 hasn't been sold as seed for about 20 years by the original company (not that there is any reason to believe that Shiva Skunk is any different at all), the phenos that people have as clones or Canadian seed may not be so representative of either the original or now Sensi NL5xSK1 seeds. In places where the "M39" is commonly sold I suppose people get tired of the same old pot all the time. I can understand this especially because NL5xSK1 is heavy tiring indica. I can't compare commercial "M39" to Sensi product because we don't get it in this part of the country, it seems to be an Atlantic side thing. I've never smelled bags that smell like Sensi's product. The Asian gangs that run much of the drug trade in Canada - and I guess commercial growers in general - probably don't have much interest in quality, flushing, or waiting for the right time to harvest, and are just looking to put out as much product as possible.
Friesland was SSSC M33.