At this point, the available evidence strongly suggests that Justin Posey shared clue-related information with the Misfits, and that both he and members of the Misfits misled people about it. Images, text messages, and voice chats have reportedly surfaced that support these allegations of corruption in Beyond the Map's Edge.
Regarding the cipher, I was informed that the cipher solver was one of only two seekers invited to Justin Posey’s private birthday party, and that even more images can corroborate that. I was also told that Ema from Treasure Hunt With Us, who manages Justin Posey’s public Discord and private Facebook group, helped arrange the connection. Even without direct assistance, that level of access raises obvious fairness concerns. Personal proximity to the creator can provide insight into his thinking, references, habits, and communication style that most seekers would never have. She had that access, and then she solved the cipher. At some point, it is fair for people to ask: what are the odds?