There were apparently a lot of problems with Lykos. Ars goes into a bit more detail: https://arstechnica.com/science/2024/08/mdma-for-ptsd-three-studies-retracted-on-heels-of-fda-rejection/

The FDA and its advisors identified flaws in the design of the clinical trials, missing data, and a variety of biases in people involved with the trials, including an alleged cult-like support of psychedelics. […] FDA advisors also noted the public allegations of a sexual assault of a trial participant during a Phase II trial by an unlicensed therapist providing the MDMA-assisted psychotherapy. […] For the conflicts of interest, the journal claims the authors did not fully disclose their affiliations with MAPS and its subsidiary—the MAPS Public Benefit Corporation—despite the fact that MAPS funded the studies.

Those are some pretty big red flags.