The Daily Star says a source close to the Blues chief insisted Villas-Boas did not - as he claimed - tell Mourinho to his face he was unhappy about only working as a scout at Inter and that he wanted a promotion.
The source said Mourinho only found out about his gripes when he was confronted by a member of Villas-Boas' family on a plane, flying back to Italy with his wife and two children after a break in Portugal.
"Andre had been talking about Jose behind his back," he said.
"Everybody at Porto was speaking about how badly he had treated Andre and then calling Jose a son of a b****.
"You know how it is, you tell someone, he tells someone else, and so on.
"Everyone was thinking Jose had been very unfair to Andre. But the truth is Andre never spoke to Jose directly.
"Jose only found out from this family member, I believe it was Andre's brother-in-law, when he was flying back with his family after a break in Portugal during his second season at Inter.
"At first the conversation was a pleasant one, everything was okay.
"But then this family member started telling Jose that Andre was not satisfied, he was unhappy, asking why he did not give him any opportunities in the field and why he was still having to do the same scouting work.
"Jose was astonished. It was crazy. When he saw Andre he asked him why he had not come to see him in his office to talk about these things - why he'd had all the discussions with his father, his mother, his family, his friends and not Jose, who had given him his first opportunity at Porto and also taken him everywhere with him, to Chelsea and Inter.
"Jose has always helped people and if Andre had come to him they could have talked about him having more responsibilities or helping him to get a coaching job at another club.
"Jose was happy with the work Andre had been doing for him. He was being paid very well, more than a coach at a First Division team in Portugal.
"He told Andre he could stay with him if Jose did not leave Inter at the end of that season, but if he went elsewhere they would no longer work together."
For breaking stories and all the great banter like us on Facebook: facebook.com/tribalfootball