Thank you for letting me know that the redditor wasn't lying about this!
"The official story is that Ariana Grande's hit "R.E.M." from her album Sweetener (2018) originated from a scrapped Beyoncé demo called "Wake Up," which was originally a T-Pain demo; Pharrell Williams, who worked with both artists, gave the song to Ariana, who then transformed it with new lyrics but kept the dreamy chorus, a process she confirmed herself. Beyoncé's demo featured her vocals and lyrics, but she never released it, and it eventually found a home with Grande, who acknowledged it as a reworked but new song."