Yeah, it was definitely intentional but it’s complicated.
Liu Weikun knew from the very beginning that as a Ghost Alpha, his pheromones and knotting would slowly force Yeehyeon (a Diamond Dust/Beta) to transform into an Omega. This isn’t something accidental in the story it’s a known biological outcome.
The key part is that he chose not to tell Yeehyeon. He kept the entire “Changing” process a secret while continuing the physical relationship, fully aware that Yeehyeon’s body was being altered. So in that sense, yes it was purposely done.
https://oceanstale.com/diamond-dust/dd-6-3-without-hiding-anything/ read here it was the time of reunion

Read novel still can't believe how easily mc forgave him for changing him from beta to omega with most dumb reason that he did for mc like whatttt (/TДT)/ with the most cliche virgin x playboy trope that I hate the most.Even when they apart the ml was constantly monitoring him and all the mcs thoughts throughout the time apart were of ml in which mostly about how much he can't live without ml blah blah.I could never understand the authors from Koreans with their double standard of having mc virgin while ml having experience and making whole power imbalance