
Besides the chance of low pregnancy risk & delayed heats. A Hyper recessive omega don't really leak pheromones like maybe 2-5% but moreso only during a heat. Where a Recessive leaks 10-20% pheromones & you also will still be able to tell their an omega if you spend a little time around them. Where a Hyper you could be in a room w/them for hours and wouldn't notice their omega. Also medications could play a part. Suppressants could work on a recessive where they never work for Hyper recessive. It just really depends what direction the author chooses.

Yea I have 2 theories
1. Was that he has always been omega he just never produced any pheromones and one of his glands was suppressed. So not only could he not produce pheromones but nor smell them. Although Doyoon is a hyper Dominant he wasn't really fully blasting Ian with pheromones neither caused he except the idea of him being a beta. But I do think it could've been times were he was subtle letting them out. Then when he went into heat his pheromones were so intense that a regular omega or maybe an recessive omega would've crumble at the door and maybe passed out. And Those strong intense pheromones is what hit the switch on his suppressed gland and it just pour out like water.
Then my 2nd theory is that he constantly just kept blasting him with pheromones breaking down his glands then when he went into rut it was like in overdrive. And he unknowingly digest and absorb so much Hyper Dominant pheromones that his body started producing an Omega gland to accompany the intense excessive pheromones
In chapter 3 Doyoon asks Yejun if he's a hyper recessive omega. whats the difference between hyper recessive vs a plain recessive omega. I've never heard the hyper version before