Turns out, there's a good reason Scott Disick's been partying in Miami the past couple days ... he pissed off the Kardashians.
Sources close to Scott tell us ... he secretly flew a girl to Costa Rica -- where the Kardashians were filming their show -- and put her up at a hotel where the crew was staying. It's pretty clear ... the Kardashians didn't want an interloper while they filmed, so Scott tried to keep it on the QT.
We're told someone from the crew ratted Scott out, telling Kris and Kim about Scott's muse. Our sources say Kim and Kris had a ferocious argument with Scott. It had nothing to do with Kourtney ... that relationship has been over for a long time. They felt it was disruptive and disrespectful.
Scott didn't see it their way and bolted to Miami. It's unclear what happened to the girl, but days later he was with another chick ... and the next day still another.
Scott, we're told, is more than happy hanging in Miami ... way happier than shooting the show.