According to Reality Steve spoiler blogger Steve Carbone, Sierra made allegations against Michael during the filming of Bachelor in Paradise's Season 8 reunion show on November 4, but those allegations never aired on Tuesday night's episode.
On November 7, Sierra tweeted that she was resting "in peace" knowing she had "receipts" that could prove her allegations. Instead of blowing up Michael's spot, she said she was "letting things be."
She wrote on Twitter at the time, "Proud of myself for letting things be when I definitely didn't have to. Bless the haters of #BachelorNation."
Sierra told Us, "I think, at the end of the day, I still took the high road and I still am treating him with respect even with the shade. And that says something."
Carbone reported that Sierra claimed at the reunion taping Michael had essentially led her on, even after he ended their relationship.
"[Sierra] said Michael kissed her 3 times after they broke up and was under the impression there was still a chance," Carbone tweeted on November 5. "Michael denied doing that."
And Sierra also allegedly told Michael at the reunion that she wished he had admitted he just wasn't feeling it with her rather than saying he was still guarded and not ready to invest himself in a relationship following the death of his wife, Laura Ritter-Allio, who passed away from breast cancer in early 2019.
"For clarity, Im over Michael & have been. This is why I dont understand why Im a point of topic for them. Those who keep saying 'get over it'... Its comical bc Im in a relationship," Sierra wrote on November 18.
"But damn near 40 & hating on a 27 yr old that also had your man? Good bye. My feelings are valid."
After Sierra self-eliminated from Bachelor in Paradise with a broken heart, the show welcomed Danielle into the cast just in time to save the 38-year-old single father from a Rose Ceremony elimination, and then Michael and Danielle immediately hit it off and proceeded to date in Paradise.
Last month, Sierra expressed how she felt "disrespected" by Michael's actions and how his "convenient" romance with Danielle has been playing out on the show.
She also accused Michael of using and dating her as a means to "kill time" while he allegedly waited for Danielle's arrival on the beach in Mexico.
But Sierra insisted she still wants the best for Michael.
"Even at the end of the day, no matter what, even him being with Danielle, I want him to have his happy ending too," Sierra told Us.
"I just obviously wish it was handled differently. I wish that he handled it a lot more respectively and more maturely than had happened."
A fan speculated how producers were likely hoping Michael would accept Sierra's rose and then Danielle would be introduced to the men at the Paradise resort as part of "The Split" twist.
Michael wrote in response to that theory, "Taking a rose when [your] heart's not in it is 'leading someone on.'"
The fan guessed that Michael's decision to dump Sierra right before a Rose Ceremony probably threw a wrench into producers' plans and so they sent Danielle to the beach with minutes left to spare before the women handed out roses.
"Choosing to end my only relationship when I was gifted a constellation and didn't have a rose was not a 'good look' but I knew that," Michael acknowledged.
Michael later claimed in his TikTok video that he did not know Danielle, a model and former Nashville-based neonatal nurse, was coming on the show, refuting allegations against him that he had been waiting for Danielle's arrival and using Sierra as a placeholder.
"No one on the beach knows who is coming down... [well] at least I didn't," Michael insisted.
The fan added how, if Michael truly knew Danielle was coming to Paradise soon, he probably wouldn't have risked his elimination by breaking up with Sierra before the Rose Ceremony.
"Not a smart idea," Michael agreed. "I still should [have] handled the breakup better, that's on me."
Michael and Sierra made an early connection on Bachelor in Paradise, but Michael eventually determined something was missing between them and his grief was preventing him from letting his walls down.
When Danielle stepped foot on the beach, Michael seemed ecstatic and affectionately called her "Dani." They had spoken via DMs on Instagram prior to filming the show, which also prompted Sierra to question the pair's "little bit of history" in a Twitter post last month.
But Michael and Danielle -- who lost her fiance Nick Haag to a drug overdose in 2011 -- claimed they were only friends and had never met in person before.
On Bachelor in Paradise'sreunion Tuesday night, Michael announced that he's "in love" with Danielle and she has changed his life for the better. He shared how his son James loves Danielle and they get along fabulously.
Danielle revealed she plans to move to Akron, OH, to be with Michael and James, although she won't be living with them under the same roof.