YoungBoy recently resurfaced on Instagram ... to throw subliminals at Kodak Black and, apparently, to very openly shade NoCap.

In an IG story, Youngboy accuses him of throwing undercover disses behind closed doors, and said they no longer collaborate because the respect is gone!!! Well, that's the cleaned-up version ... but you get the idea.

NBA also claims NoCap owes him money ... which was further explained through NoCap's fiery response.

According to him, NBA tried to charge him for their last collaboration, "Flags to the Sky," which appeared on the Alabama rapper's "Mr. Crawford" album.

"Mr. Crawford" was released through Atlantic Records and NBA's Never Broke Again imprint ... and NoCap can't believe his own label boss would try to tax his pockets.

NoCap alluded to the Kodak cheap shots while claiming he never badmouthed NBA, but also says he's never been supported in his 3 years signed to the label.