he's an alpha that's undergone the medicine to make him into a fertile 
omega to hold a baby & so I think maybe a side effect of the thing is causing him
to give off omega pheromones but when he's not in heat maybe he just keeps his 
alpha pheromones

but it could also be him being ho*** to give off omega pheromones to attract a mate. 

It could be his pheromones interacting with the other alphas 'mones. 

he's for sure alpha but went through that process to be able to conceive a baby for 
the throne. That's why this may be confusing. Go back to chaps 1-