Since shallots vary so much in size, I never worry about whether it's one or two. I just chop what I think is appropriate for the recipe. Sometimes I get shallots that only have a single lobe.
The same is true for onions & garlic. Sometimes one clove is three times the size of another. And if the recipe isn't specific about size, then what exactly is one onion?
When shallot is growing, it multibly itself to two, so in picture is already two shallots. Its a similar onion like a potato onion (known also as multiplier onion) what produces many new onions from one.