Audio problem: After Jade enters the coffee shop she says "Dennis, Darling!" and immediately afterwards you can hear a crew member/the director saying "Cut." Then the scene continues from a different camera/angle. (00:07:20)
You Can Go Home Again - S7-E10
Other mistake: When Denise hangs up the phone after inquiring about the two bedroom apartment, actress Lisa Bonet's multiple tattoos are visible on the back of her neck and shoulder. In every other scene her tattoos are obscured with makeup as they wouldn't fit with Denise.
Other mistake: When Denise and Rebecca are in the kitchen, Denise is playing a tape recording of the rap session from Uncle Wilton when they were doing the math rap. However, when Denise was attending the class, she never had a tape recorder, so there is no way she could have recorded anything.
Chosen answer: That is the song "Open the Door Richard."