During Sunday night’s BET Awards, while Mindless Behavior and Mike Epps were presenting the award for “Best R&B Artist” … in response to Mike Epps’ bad singing, one of the group’s members (Ray Ray) made a joke referring to Lauryn Hill‘s tax woes:

“You sing BAD … like Lauryn Hill’s tax accountant bad.”

The zinger brought out gasps from the audience, including Beyonce, who did NOT think the joke was funny.

In fact, according to TMZ, Beyonce — who ended up winning the award for the category — was so upset, that she reworked her acceptance speech on the fly to include a shout-out to the former “Fugees” singer. “I want to thank all the talented R&B women that came before me like Lauryn Hill and Mary J. Blige,” she said.

When B walked off stage, there was a woman waiting for her — possibly a BET handler — and B began to vent about the insult, saying the Lauryn Hill diss was “disrespectful” and “not cool.”

The woman complimented Beyonce for adding Lauryn Hill’s name to her acceptance speech … to which Beyonce replied, “I just felt [the diss] was wrong.”

The next day, Mindless Behavior apologized for the diss, tweeting:

“We meant no disrespect to our girl Lauryn Hill last night, it was a bad joke. We’re big fans and hope you’re not mad!”

Kids…