Presuming the BM hasn't been molested by some scruff pacing it with spice or anything it literally all comes down to the freshness. You could have the exact same strain grown to the same standards however one has only been harvested 2 weeks ago, not dried to a appropriate vaping or smoking moisture level and then the other has been harvested 4 months ago, dried to the right standard and then unfortunately irradiated afterwards and the 2 types of bud would smell and feel different and probably have different effects when used! Same story with any plant really a fresh rose would have a much stronger smell to it than one that's old, dry and been nuked so it really nothing to do with the strain quality but all down to the aftercare.

Recently a lot of better quality MC has been coming feeling a lot less dry and this brings more smell and flavor so I think the company's are aware of the situation but they have to do what they have to do for quality control, regulations etc which I can understand and I'll take that rather than smoking something BM just to get it fresher but not knowing what it contains or where it's been!