Someone explain S8E7 Chelsea's house

Halfway through E7 and what the fuck is happening in that scene? Why did they randomly call Bre up? What was the point behind that? Genuinely confused what their motives were. Why would Chelsea want that drama and why were Emma and Chrishell supporting her?

Was there anything that Bre made public that caused Chelsea to ask her friends to call Bre up? Surely she didn't just randomly question Bre's motives and call her after their face to face talk, unless Bre said something publicly. And the fact that Chelsea hadn't even talked to her husband before any of this. Why would she grieve, not talk to her husband, and then suddenly out of nowhere question Bre's motives and call her up without getting all the stories straight?

Mary was right. I love Chelsea but she really might be a pot-stirrer.