The outing in Beverly Hills, California, with Rob's sister (who was wearing a shirt by Enfants Riches Déprimés) comes less than a week after hanging out with her proclaimed "lil sis" Kylie Jenner.
Though Rob and Chyna's engagement earlier this month created friction in the family – and the Kardashian-Jenner women have yet to publicly congratulate the couple – they do appear to have buried the hatchet since last week, when Kylie and Chyna got together for a headline-making selfie and claimed they'd "been best friends the whole time."
Of their reconciliation, a source told PEOPLE Kim, 35, "definitely" played a role, arranging the meet-up because she wanted Kylie and Chyna "to stop the nonsense."
Of course, "the idea that Kylie and Chyna have been BFF's all along is obviously silly and and not true," added the source. "It started off more like the saying that you should keep your friends close and enemies closer. Kylie, however, seemed relieved about getting together. She is growing up too and doesn't like all the drama."
The source also said the Kardashian-Jenner family are starting to warm up to the idea of Rob marrying Chyna.
"Everyone knows that Rob will go ahead with the wedding, so his family is now making an effort with Blac Chyna. Kris [Jenner] wants to get to know her as well, since Rob seems happy," said the insider.
And while a source recently told PEOPLE Rob and Chyna aren't "planning to have a long engagement," the happy couple still hasn't tied the knot – despite Rob calling Chyna his "beautiful wife" on Instagram.
Of the affectionate call-out, a source tells PEOPLE Rob and Chyna are not married yet, but that he uses the term "as a cute nickname for Chyna."
In the meantime, fans of the famous family and their drama can tune in to Keeping Up with the Kardashians for more – a sneak peek at Sunday's upcoming season premiere promises quite the blowout – and over none other than Chyna herself.
Keeping Up with the Kardashians season 12 premieres Sunday at 9 p.m. ET on E!