Cardi B’s alleged backstage meltdown over a Nicki Minaj gag may have shaken the walls at 'SNL' ... but we're told there's no hard feelings!

Sources close to the situation tell TMZ ... Cardi was having a bad night, just like anyone else has from time to time -- adding while the show doesn't condone such behavior, nobody's holding any grudges and she's still welcome to return.

That’s a pretty big olive branch, considering Cardi's alleged behavior after catching "Weekend Update" anchors joking about Nicki’s recent MAGA ties -- as Cardi was gearing up for her Jan. 31 music guest spot.

Cardi allegedly hurled her phone at a TV monitor, threatened to bounce, and much more -- very much signifying her and Nicki's never-ending flame war is still going strong.

In the end, the joke got yanked -- and 'SNL' has now made it clear to us they're not gonna be yanking Cardi from the air. She walked away untouched, unbothered, and is very much invited back.