Hypothesis:
Molecularly speaking in the body, cannabis binds to something that normally NAC binds to.
Cannabis knocks off NAC, which is a nonessential amino acid but is tremendous in helping the body function well.
The reason cannabis remains for a long time for long time users is because cannabis has "permanently" bound itself to the something that normally NAC binds to.
Solution ?
Keep taking NAC pills as long as you're using cannabis.
Keep taking NAC pills until the effects of cannabis is gone, even after DONE using cannabis.
Taking the drug test in a couple of months, and just throwing this out there.