It may have started just before UFC 268. I can't find online what John Morgan initially said to Colby that caused Colby to get pissed off, but this is what Colby said to John Morgan at the UFC 268 pre-fight press conference after John asked him a question:
"John, you were getting real slick with me yesterday. You're a clickbait merchant. You were saying I was undeserving [of the Kamaru re-match] and didn't deserve to be here. Well guess what? You're undeserving of an answer from me."
Then Colby went off on his flabby butt mock tirade, which he continued yesterday.