I have been required to take 2 weekly drug screens. I've used flower maybe a total of 4 times while being required to do this. My main use is vaping, using 500mg ceramic cell cartridges. The distillate is extremely pure and potent. Viscosity is extremely thick, moving slower than molasses. I've been told I have sporadic marijuana use, but have been giving negative samples. The last time I used flower was just under 1 month ago and I've been giving clean samples the last 2 weeks. In that time I have hit the pen several times throughout the day. I have even done so a couple times right before giving my sample. Any ideas as to what may cause this? Perhaps the chemical that is found in the analysis is distilled out?