It's not that she's using the wrong shade of makeup. It's possibly the wrong tone which it's why it appears so yellow.
Darker women have a harder time finding foundations to match their undertone. Just because MAC carries 3 shades of dark doesn't mean they work on all dark women. Some dark women have a red undertone and others have yellow and purple. Her makeup artist found a shade that may be in her range but the yellow in her makeup isn't working. She appears to need a reddish base which is very hard to find.
Also darker women's faces may be lighter than their bodies and vise versa. So blending and choosing shades aren't as easy for darker women as it is for lighter. She may have looked great in person but the camera picked it up