You are missing the second after this, she lifts her right foots and shifts her weight left to then step back onto the mat with her right.
Her left foot was completely off the mat, her right foot on - if she would have kept her right foot planted on the red no out of bounds BUT and she shifted her weight to her left foot that was off the floor and lifted the foot on the red to take a step back on the mat. As soon as she lifted the foot on the red, her only 'touching' foot was OOB making her out. It's not a traditional OOB where someone completely clears the floor with their whole body but without one body part in contact with the mat it is an OOB per definition.
The confusion lies in the difference in wording from the Varsity deductions vs the USASF deduction. Varsity's specifically states that both feet must contact outside the floor and border. The USASF version is rather vague and probably needs to be addressed to make it more specific to what does constitute an OOB, not just both feet off the surface and border. The word "off" gives a lot of room for interpretation. This deduction meets the letter of law for USASF deductions.