Cardi's legal team was in court Monday -- without the rapper -- for a hearing about the August incident. We're told prosecutors expressed their frustration that Cardi herself was a no-show considering they've already given her a 6-week extension on the case ... so they asked the judge to issue a bench warrant.

The judge denied the immediate request, but did issue a serious warning -- Cardi must appear in court Friday morning -- or there will most likely be a warrant issued.

Cardi's defense team also revealed in court they've been having a tough time getting in touch with her directly -- instead only communicating through Cardi's management team -- and only found out Thursday Cardi had a prior commitment that would prevent her from attending Monday's hearing.

TMZ broke the story ... Cardi is accused of unleashing her posse on 2 strip club bartenders -- Jade and Baddie Gi -- and badly injuring both. Jade told us ... prior to the attack, Cardi had threatened her for months, accusing the two of sleeping with her husband, Offset.