Since then, things have been strained between the mother and daughter, with Mandy even coming out and saying that she couldn't convince Selena not to work with controversial Woody Allen.
However, now she's directing her aim back at Justin... and, well, Ariana Grande.
While hosting an Instagram Live earlier this week, Ariana's rendition of "Beauty and the Beast" from the live-action remake of the movie came on the radio.
"So sad," Many said after the song was playing for a few seconds. She then groaned to her daughter Gracie, saying, "It's Ariana Grande."
She then decided to switch the radio to a different station, when it landed on Justin's "What Do You Mean." Clearly displeased, she shut it off.
Fans sort of understand Mandy's disdain for Justin, but they're extremely confused about what she has against Ariana, since Selena and Ariana have always been on good terms.
So far, 2018 is the year of Mandy Teefey causing dramz.