Every author likes to put a twist on their version of the omegaverse so it could be a little different
Lame....
I don't think they do it just for the sake of being original, it is just that there are not stablished rules, so they just use the rules that best resonates with them or that best fit with their story.
Artistic license 'periodt'...unfortunately the page with the omegaverse rules for this manga haven't been translated so we cannot figure where else it may deviate from the norm. Love is an Illusion had pairing without a bite, some stories have dominant and recessive alphas and omegas; other stories explore the fated pair vs common pair bonds and on and on. All u can count on is omegas will be the oppressed, betas will be the majority and alphas are the powerful ones. http://www.mangago.zone/home/mangalist/334330/
Why is Omegaverse so inconsistent??!!. So if they are pairs isn't only his pair now supposed to be affected by his pheromones???