
HAHAHA i’ve been on the web for a few hours now. yes it is like that, that’s the strongest reason he had in mind. but i’m still questioning about why other alphas react to his heat pheromones when the one who should get the effect of it is only his pair aka shiina. that’s what i always see when i read other omegaverse manga, so far. that’s why creating a bond is the safest method to stay out of any unwanted things.

Oh, it's not set in stone that all omegaverses have to follow the same rules. So in this world, apparently the author made it that the omega still attracts others outside of their marking (which makes no fucking point for the marking author-san. NO FUCKING POINT.)
You smart, the author isn't. That's all I've gotta say ¯_(ツ)_/¯
wait wait wait, rika already got his neck bitten by shiina when rika got into his heat and ever since that time they bound to each other, ok.. but if an omega already has a pair and they go in heat, it shouldnt be attracting any other alphas right? it should only effect their alpha pair, not other alphas as well? damn this is a bit confusing, the plot is going too fast and there are lots of unexplained things.