The two gave a memorable fight which saw both fighters slug it out like street fighters. They drew as much bad blood as they can muster.
After the fight, the post press con saw Nate Diaz vaping cannabis (technically referred to as CBD or a cannabidiol oil).
His problem started with the fact that this is a banned substance. The World Anti-Doping Agency and the United States Anti-Doping Agency considers cannabinoids as such.
Nate vaped the substance during the press con that happened right after the fight. It arguably falls into the 6 hours before and after in-competition window.
Nate Diaz should have known better.
That hit may have caused him to temporarily forget the rules.
Goodluck on your next fight Nate!