Swift's former label head Scott Borchetta published online text messages allegedly sent by Swift in November 2018 in which she appears to say it "meant more" to her to bet on her future than her past.
"Since communication ran dry on our negotiations, I've done what I told you I would do and gone out exploring other options," Swift allegedly wrote, regarding her signing with Universal Music Group.
"Owning my masters was very important to me, but I've since realised that there are things that mean even more to me in the bigger picture. I had a choice whether to bet on my past or to bet on the future, and I think knowing me, you can guess which one I chose."
Page Six's source says: "She got caught crying wolf again", referring to Swift's widely publicised feud with Kim Kardashian and Kanye West.
Swift slammed West for writing about her on his song Famous, claiming she never gave her approval, however Kardashian shared videos online in which Swift seemingly gave her blessing and said featuring in a Kanye song was "like a compliment".
The source added: "(Braun)'s been nothing but supportive of (Swift's) career and one of her biggest fans. You don't make a $300 million bet if you don't want to win."