Here is detailed information about what SM admittedly lied about that:
The next morning, around 5:45 a.m., Melissa said she went through her usual routine of opening the kids’ doors and saying good morning to them. She told Dateline she saw Karlie in her bed at that time. Melissa said she then went back to sleep for a little bit. But when she woke up a little bit later and opened Karlie’s door again, Karlie was nowhere to be found.
“I went back into our bedroom and I said [to Zachary], ‘Honey, she’s not here.’ And he said, ‘What do you mean she’s not here?’” Melissa said. “I said, ‘She’s gone. She’s not in her room. She’s not outside. She’s not in the backyard. She’s not anywhere.’”
“Melissa, you told NBC, the next morning that at 5:45 a.m., you did your usual routine of opening up the kids’ doors, saying good morning, getting them ready for school -- that sort of thing. Did you – she was still in bed at that time. Did you go back and lay down?” Dr. Phil asked Melissa on the show which aired on March 25, 2019.
“No. That – the Dateline NBC?”
Melissa answered. “Yeah, that was a false story. Because I wasn’t – it was a lie about checking in on Karlie. Because it was in the beginning, and I didn’t know what to say and – I shouldn’t have even done the interview.”
Sixteen-year-old Karlie Gusé missing after vanishing from California home
There is also the Nancy Grace podcast where she admits to lying about the clothing Karlie left the house in:
Karlie Guse stepmom admits: I gave the wrong description of my daughter's clothes from Crime Stories with Nancy Grace
There are other details as well, such as the location of Karlie’s cell phone. This is a he said/she said so no link to verify. SM says Karlie’s phone was on kitchen counter but BF says he saw it next to Karlie’s bed that morning.
These are the 3 misinformations I have heard of. But why lie about any of these? Strange for sure