Well, that part is a bit foggy, as The Mirror reports that a fight with Zayn was part of Paul's decision to pack his bag and leave the boyband behind.
A source told the paper: "There have been issues behind the scenes for a while, and they've finally come to a head leading to Paul's relationship with the band coming to an end."
The insider noted that Paul's "babysitter" role went beyond being an employee: "In many ways he has completely run the show while they've been on tour – they even call him Daddy. He became a friend as well as a key part of their management set-up."
The source added, "He's always been at the heart of the One Direction team, and it's hard to think of them going on tour without him there."
Right now, there's just loads of speculation over what happened to cause Paul to leave the job...and, of course, more 1D breakup rumors are swirling over it.