It all came to a head in the new clip when Kim threatened to fire Kourtney from the show altogether.
Kourtney has now posted a clip of her sister Kim from the latest episode of KUWTK, with her own commentary on top.
Kim says to the camera: "Kourt spends a lot of time off-camera. I'll see things that I read about online and wonder 'did this really happen? Is she talking to this person?' And realise that it's true but she's so secretive with us that she won't even tell us."
Kourtney wrote over the clip: "' A lot of time' but filming 5 days a week. Let me live."
The next clip Kourtney simply writes: "Damnnnnnn", as Kim yells : "If she doesn't want to show up, if she doesn't want to work, then that's it, she's out."
Shortly after Kourtney blasted her sister all over her Instagram Story, Kim posted an incredibly pointed photo on her own Instagram of her and sister Khloe Kardashian.
"My Ace! ♠️" Kim wrote, reinforcing the comments she recently made about getting along with Khloe the most out of all her sisters.
It was both Kim and Khloe who were attacking Kourtney in the earlier clip from yesterday.
"If I have boundaries, respect them. Just because you love to show every single thing..." Kourtney yells at her sisters, before Khloe interrupts with, "I don't like to...that's our job."
Kim then spoke to the camera: "Our job is being open and honest and sharing a lot of ourselves, and it just seems for the past few years now, Kourtney hasn't really been open about her personal life on camera. So all of the days that Kourtney isn't filming, Khloé and I are picking up the slack and having to share more. Cause if we're not sharing our lives, then what is the show?"
Khloe then snaps at Kourtney, saying, "you don't give anything, you coast. You think it's fair that you just coast through life?...I would rather share never a thing."
It was recently reported that the KKW Beauty founder has been cutting Kourtney "out of the loop for months".
An insider close to the family told Radar Online that Kourtney didn't leave the show because she wanted to, but because Kim forced her out.
"Kourt is accusing Kim of forcing her off the show by belittling and cutting her out of the loop for months if not years now," the friend revealed. "She’s convinced this all started because Kim got jealous that she was losing her divine right to be next in line to her mom, and bit by bit she’s used her influence to undermine Kourtney at every turn."
It also adds to that rumour that the sister's fight as soon as the cameras are turned off, and are apparently unable to "be in the same room as each other".
"Kourtney has hated Kim for a couple of years now. She thinks she’s vapid and mean," an insider told Radar Online in October. "Their egos have clashed big time and when the cameras aren’t on, they don’t speak. There are hints of their feud, of course, but the reality is they genuinely can’t stand each other.
"Kourtney has much better things to do with her time thank kiss up to Kim," the source continued, adding Kim believes Kourtney "would be nobody without her".
