apple air pod tone problem ?

I noticed that when I put my air pods in one at a time it only makes one tone in one of the ear buds to say that they are ready for use. But when I put them in my ears at the same time I hear the tone in both of them is this normal I always assumed if you put them in one at a time the tone would sound for both but that doesn't happen unless I put them in at the exact same time .