The 38-year-old reality star ended her tumultuous on/off relationship with Scott - with whom she has three children, Mason, seven, Penelope, five, and Reign, two - for good in 2015, but in a new preview clip for their reality show 'Keeping Up with the Kardashians', younger sister Khloe isn't convinced the pair are really over.
After Scott, 34, confronts Kourtney - who is now in a relationship with Younes Bendjima - about not being invited to Khloe's surprise birthday party, the 33-year-old beauty steps in to comment on their relationship.
Speaking in the clip, Khloe tells the pair: ''You guys are so f***ing dysfunctional. I don't know if this is some thing you guys do as foreplay but this is f***ing nuts.
''You two are so f***ing nuts seriously. And the fact that you waste my time when you guys are now just gonna go get mani [or] pedis.''
Kourtney then insists that she and Scott - who has since moved on with 19-year-old Sofia Richie - no longer ''hook up''.
But Khloe adds: ''You guys are f***ing sick!''
In a previously shared clip of the upcoming episode - which will air on E! on Sunday (12.11.17) - Scott hit out at Kourtney for not inviting him to the family bash.
He said sarcastically: ''F**k, I didn't even get invited to her birthday. And I'm family. That was really sweet. That made me feel really good ... I highly doubt that Khloe was like, 'The last person I'd want at my surprise party would be Scott.' It's cool. Honestly, I called my sister and I hung out with her the whole night.
''And then, actually, I called my mom after and was [like], 'Hey, mom. Do you want to come over? Because I'm feeling a little down and lonely because the family that claims I'm still blood even though we're not together still doesn't invite me to a surprise party.' But I really felt good about it.''
However, Kourtney defended her decision to keep Scott off the guest list.
She said: ''I didn't want to have you coming to the birthday and be photographed going in. I'm a little bit caught off guard. I was trying to be positive. I didn't want to say I just didn't want you there. So, if I can't say anything nice, I just won't say anything at all.''
Who inspired Yes We Mystic?
A rising country star opens up about the UK scene.
From the salt mining town of Winsford in Cheshire, The Luka State came to play in the underground confines of The Forum Basement.
She unveils her first solo album in the form of the Judy soundtrack.
From Duran Duran to Weezer, it's an iconic day for music.