A lot of folks noticed that after Cardi stopped the show Saturday to retaliate against a woman who threw a drink on her from the crowd ... the music/song she was rapping to, 'Bodak Yellow,' kept going, and many have assumed that Cardi was just lip syncing.

It was quite noticeable ... but, obviously, more people focused on what was going down between Cardi and the lady -- who appears to have been hit with Cardi's mic (good aim).

Now, in the aftermath, the jokes are flying at Cardi's expense ... 'cause some trolls are (falsely) equating her to Milli's Rob Pilatus and Fab Morvan -- who were notoriously caught lip syncing back in 1990 during a live performance ... when their record skipped mid-show.

Not only were the Milli Vanilli dudes exposed as in a lip sync sense -- but it was later revealed that they weren't the ones singing in the first place. Indeed, very scandalous.

In the wake of CB's dustup ... some are throwing her into the same category, but it's apples to oranges for a whole bunch of reasons -- which many on Twitter are rightly pointing out.

For starters, it's common these days for artists to use backing tracks for their performances. In fact, it's SOP when it comes to modern-day shows ... especially rappers. All the big acts do this, and they simply chime in on top of it live -- often deviating for added entertainment value. In Cardi's case, there's no evidence she wasn't rapping *with* the backing track.

And just for the sake of argument, even if she was lip syncing here ... it's NBD, really.