The KarJenner matriarch was out in the desert Friday night alongside her partner, Corey Gamble, but they weren't cruising alone -- on the contrary, there were a few private SUVs that pulled up to the VIP entrance area ... and the Amazon founder stepped out as well.

Of course, he was with his lady as well ... and they seemed to be rolling with a small group of friends/couples. Everyone was in their best music festival getups -- JB especially.

They stood around and chitchatted before being led to a secret back route to the main stage ... where they were set to watch Bad Bunny perform for the second weekend in a row as a headliner. Remember, he had a memorable outing days ago with Kendall Jenner.

Unclear if the Gen X crew here was on the grounds earlier in the day or not -- there don't seem to be any pics of them floating around from what we can see ... but they certainly rolled deep for the evening sesh. Gotta imagine they hung it up after that, though.

Anyhoo ... it's an interesting pairing, but not surprising. We already know Kim Kardashian has had face time with Jeff and Lauren -- so it follows that Kris would know them too.

The question, of course, that must be asked when you're chillin' with high rollers like this is ... who picks up the check for a big dinner? Kris is rich, Jeff's way richer -- maybe Corey???