Kourtney Kardashian Calls Kendall Jenner 'Uptight' and 'Sensitive' While Khloé Tries to Mediate

Some sister-sister drama came to a head on this week’s Keeping Up with the Kardashians.

On Sunday’s episode, tensions between Kendall Jenner and Kourtney Kardashian began brewing after Kourtney, 40, tagged along on a ski trip to Mammoth, California, with Kendall’s friends in January. Back in Los Angeles, Kendall, 23, opened up to Khloé Kardashian, 34, about the fact that she felt their older sister had been making jokes at her expense throughout the trip.

“You know, Kourtney and I have been getting a bit closer over the past couple of years and I love that she hangs out with me and my friends,” she explained. “But to be honest, I felt like there were just some moments where she was a bit rude and it really started to get to me at a certain point.”

“A lot of the trip, people were picking on me, and by people I mean Kourtney, most of the time,” she continued. “Whether she thought she was joking, I didn’t really think it was a joke. I just felt like she was trying to be cool in front of my friends and like, younger people that are cool, at my expense.”

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Kourtney, meanwhile, had no idea how her sister was feeling.

“I thought maybe Kourtney would apologize for the way she was acting on the trip, but it seems to me that she’s pretty oblivious,” Kendall said. “She has no idea what’s going on. It’s just awkward right now and I’m over it.”

The situation was finally brought to Kourtney’s attention after Khloé confronted her for “bullying” Kendall and making “digs” at her. Kourtney insisted they were all “jokes” and claimed that Kendall was acting so “uptight” that she wouldn’t even let the group stray from their grocery list.

“I definitely think it was unfair for Kendall to say that I was bullying her. We were just having a good time,” Kourtney argued. “She’s just way more uptight than I thought because I wasn’t trying to make fun of her at all. It’s just my personality to make jokes.”

At that point, Khloé didn’t know who to believe.

“So I have no idea what trip Kendall and Kourtney were on, but they were not on the same trip,” she said. “Their stories are so polar opposites. I’m not saying anyone is lying, it’s just they have very different ideas of what happened.”

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Back with Kendall, Khloé revealed that Kourtney had a very different spin on the trip, one that was much more “played down.”

“I don’t think she would ever straight up say, ‘Yeah, I do things to Kendall to make myself feel better or make her friends laugh or get validation from other people,’ ” Kendall said. “But I know everything that I felt is true and real.”

“Your feelings are very valid,” Khloé acknowledged. “Especially when it’s feeling like someone is bullying you. You shouldn’t have to be talked out of that feeling, someone should just stop bullying you.”

And when Kendall found out that Kourtney had claimed she wouldn’t let them stray from their grocery list, she was furious.

“Shut the f— up,” she said. “I didn’t say anything about steering off of a list. Bible. I did not say one thing about steering off of a f—ing list. I hate that she’s trying to make herself look better to make me look f—ing crazy. … That is the biggest sack of s— ever. We ended up with like, three carts and I was like, ‘Guys, we’re here for two days.’ “

“My biggest thing is wasting food. I don’t want to waste food,” she added. “Never once did I say we could not stray off the list. I was just making a point about wasting food. … This is, again, my point. She will go out of her way to make me look crazy because she’s insecure about what she did.”

“Again, these are wildly conflicting stories,” Khloé admitted. “I don’t know. I’m so confused.”

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When Kendall tried to confront Kourtney over the phone about the grocery store drama, things only got worse.

“I’m not making it up. It happened,” Kourtney insisted. “Everyone was tip toeing around you to buy anything.”

Kendall raised her voice to respond, but Kourtney immediately cut her off.

“Listen, I don’t have time to talk with a lunatic,” she said. “We can talk when you’re ready to talk like an adult.”

Eventually, Khloé decided to intervene and invited Kendall over to Kourtney’s in the hopes of smoothing things over.

“I totally understand that Kourtney and Kendall are upset, but it’s ridiculous that this fight has gotten to this level,” she said. “Kourtney is kind of cracking jokes at Kendall’s expense, but I don’t think it’s maliciously. I don’t think Kourtney realizes what she’s doing. They just need to come together and figure out why they each feel the way that they feel. They’re sisters and this is stupid, at the end of the day.”

“I’m not going to let this tension between Kourtney and Kendall linger on and drag out,” she vowed. “They just need a little kumbaya moment. There would not resolution if I don’t come in and play therapist.”

But the confrontation quickly escalated out of control after Kendall pointed out that she felt Kourtney was trying to seem “funnier” and “cooler.”

“Maybe I just am funnier and cooler,” Kourtney replied.

“It’s not a competition,” Kendall fired back.

“It’s not,” Kourtney said. “But I feel like you’re so sensitive.”

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Khloé butted in to point out that she noticed Kourtney “bashing” Kendall on the phone to one of their friends, and from there, all hell broke loose with all three of them screaming over one another, each accusing the others of “exaggerating” their stories. Kendall eventually gave up and walked out.

“This is actually getting really annoying,” Kourtney said later. “I know that Khloé is trying to be helpful, but it’s not helpful. I told her all this stuff in confidence and for her to go tell Kendall exactly what I’m saying to her, it’s only going to make the situation worse.”

But at the end of the day, the sisters will always be there for each other. After settling their argument, Kourtney and Kendall staged a pretend fight as a joke to stress Khloé out.

“Once Kourt and I kind of settled down and got the opportunity to speak to each other just us, we got to hash everything out,” Kendall explained. “We came to the conclusion that Khloé made this a little bit worse than it needed to be, so we decided to stage a little fight to annoy Khloé and freak her out a bit for getting into our business.”

“I thought I was doing a good thing,” Khloé said. “I am sincerely trying to help, but I know for next time, just let them figure it out on their own.”

Keeping Up with the Kardashians airs Sundays (9 p.m. ET) on E!