Becca, who starred on The Bachelorette's fourteenth season and fell for Thomas on Bachelor in Paradise's seventh season this past summer, apparently unfollowed Katie on Instagram after Katie had thrown some shade -- although seemingly in a playful manner -- at Thomas, Us Weeklyreported.
To celebrate the upcoming holidays as well as the re-release of Taylor Swift's "Red" album, Katie has been posting a "12 Days of Messy" on her Instagram Stories in which she matches one of her The Bachelorette suitors with a song from the album every day.
Katie's Monday post, November 15 post, which was Day 4 of her event, was dedicated to her The Bachelorette ex, Thomas, a real estate broker who currently lives in San Diego, CA.
The Season 17 The Bachelorette star posted the song, "I Knew You Were Trouble (Taylor's Version)," and then fans reportedly noticed that Becca stopped following Katie on Instagram.
The song's lyrics include, "I knew you were trouble when you walked in/So shame on me now/Flew me to places I'd never been/'Til you put me down."
Thomas had developed the reputation of being a smooth-talking, manipulative villain on Katie's season of The Bachelorette that aired earlier this year.
Katie dumped Thomas for allegedly being on the show for the wrong reasons.
Thomas admitted at the time he briefly thought about potentially becoming The Bachelor star for Season 26 in 2022, and Katie was concerned that Thomas had been using her as a stepping stone to boost his career and fame.
Katie even called Thomas "a liar" as well as "selfish" and "unkind" when she eliminated him at a Rose Ceremony. (Thomas later apologized for his insulting behavior on The Bachelorette: The Men Tell All.)
In late June, Katie said on "The Viall Files" podcast hosted by Season 21 The Bachelor star Nick Viall, "I am nervous for any woman who interacts with Thomas, honestly. He's a smooth talker. I wouldn't be surprised if he recycles some lines with me on some of these women... Good luck to them."
"If he's on Paradise, I don't care who he's with, I'm going to be like, 'Watch out, girl!'" Katie said, adding that she wasn't "open" to "changing [her] mind" about the bachelor either.
However, Katie eventually came around and even showed encouragement for Becca and Thomas' Bachelor in Paradise romance. Katie once commented on an Instagram photo of Becca and Thomas on the beach in Mexico, "Obsessed with this. [Sunglasses emoticon]. look how you look at him!"
Given the fact Thomas was a polarizing character on the franchise, Becca opted to form her own opinion and trust her gut.
During her first date with Thomas in Paradise, Becca expressed to the cameras how she wasn't going to hold Thomas' edit on Katie's The Bachelorette season against him.
"All I knew about Thomas before was that he was involved in some of the drama on Katie's season," Becca said.
"I have been blindsided in the past, but I said that I was going to come in here open-minded and with no expectations or any pre-conceived notions. So I'm going to give him a chance."
Becca and Thomas were sweet and affectionate all summer long, but Becca broke up with Thomas and ended their relationship right before overnight Fantasy Suites in Paradise, which left him completely brokenhearted.
It apparently took no time at all for Becca to reach the conclusion that she and Thomas are meant to be once they got back together.
"I'm gonna probably hate myself for actually admitting this to anyone, but I called my mom -- and even though I was engaged twice in the past -- I was like, 'Mom, I think I want to marry this guy,'" Becca shared with Mike Johnson and Bryan Abasolo during an October episode of their "Talking It Out" podcast.
"It's the first time I've ever actually said that out loud."
Becca also revealed Thomas has sent her "multiple text messages" asking about engagement rings, even though he teased her that she should be the one to pop the question this time around, referencing her previous failed engagements to Arie Luyendyk Jr. and Garrett Yrigoyen.
"It's something we've talked about," Thomas disclosed on the "Talking It Out" episode. "I mean, I don't want to spend my life with anybody else... I wouldn't want to wake up next to anybody else."
Thomas later told Hollywood Life of possibly getting engaged to Becca in early November, "If I was a betting man, I would not put money against that."