Viall handed out his final rose late last year when Season 21 of The Bachelor wrapped filming, but according to In Touch Weekly sources, the last woman standing isn't thrilled watching the season unfold on TV.
"During filming, Nick was really sweet and charming toward her. But watching back each episode, the winner is realizing more and more that Nick is a fraud," an insider toldIn Touch.
"She finds his behavior to be completely inappropriate and she feels betrayed."
So far this season, many of Viall's bachelorettes have questioned his desire to truly find a future wife.
Because of his physical chemistry with villain Corinne Olympios -- who took her bikini top off during a group date and straddled him on the floor of a bounce castle -- the women are wondering whether the Bachelor was just looking to have fun on the show and mess around.
The winner is reportedly fuming over the footage, especially because of the number of girls Viall has made out with.
"Watching Nick on the show with the other women has been really hard," the insider revealed. "She isn't sure anymore if he's ready to settle down."
Viall's behavior on the show almost prompted current frontrunner, Vanessa Grimaldi, to hand back a rose he had given her on their exciting and emotional one-on-one date. The special education teacher warned Viall that she was judging him based on his actions and was disgusted by what she was observing.
Similarly, fellow frontrunner Raven Gates made a catty comment to the cameras in a recent episode about how it's no wonder Viall is still looking for love after four attempts on reality TV when he's attracted to women, like Olympios, who lead with their sexuality.
"He's always expressing [to the bachelorettes] that sex is important to him," the insider claimed in November. "It comes off as sleazy!"
As the magazine previously reported, multiple women allegedly threatened to quit Viall's season due to his unpopular decisions and offensive antics.