Remember, Waiters reportedly took a THC-infused edible and fell asleep on the team's flight from Phoenix to L.A. back in November ... and freaked out when he woke up.

Waiters required medical attention at a hospital once the plane landed in L.A. ... and had to miss the Heat's game against the Lakers later that night.

The 28-year-old expanded on what really went down on that flight in The Players' Tribune Monday ... saying, "It's on me."

"I own that. It was idiotic on my behalf — point-blank, period," Waiters says. "What’s crazy is, my whole life I been a leader. I’m not a follower. Pat (Riley) knows me. He knows I don’t do drugs."

Waiters points out his struggles with depression and anxiety ... and says he wasn't in a good place when the incident went down.

"But sometimes when you’re going through dark times, you can fall trap to things you’d never do in your right mind."

Waiters says the reports got blown way out of proportion ... and is denying he ever had a seizure.

"Ask the doctors. Ask my Heat teammates. They can speak on it. For that b.s. to come out, it ain’t right."

Waiters was suspended 10 games due to the incident ... and was later traded to the Grizzlies. He was released 3 days later and signed with the L.A. Lakers.