"The Breakfast Club" cohost was on the air Thursday when the Master P convo prompted Envy to spill the tea -- he says he and DJ Mono were recruited by Irv for a track, and while he received the front-end payment ... he claims he was told "keep it moving" when attempting to receive his final cut.

Envy hadn't yet reached his current financial status of massive car collecting, and says he was looking forward to the money Irv allegedly owed him. He says he and Mona end up splitting the front-end payment.

We reached out to Irv's team to get his side of the story ... which only came to light because Master P is calling "fake news" on Jess' claim he still owes her $15K for her appearance in the critically panned film, "I Got the Hook-Up 2."

The No Limit Records Colonel dropped off an extensive IG post Wednesday ... claiming to have proof of the contract Jess signed. He's also swatting down Fat Trel's allegation P released some of the D.C. rapper's music without authorization, and got paid handsomely from it.

Jess insists she's still owed the 15 racks, and Trel shared a DM from P's son Romeo Miller vouching for his version of events ... which is alarming, considering father and son supposedly reconciled over the holidays.