@Firedancer885:
AO3 allows more than one series. The only indicator I'm aware of that would indicate which is the 'correct' series, is the order that they appear; FFDL assumes that the first series listed is the 'correct' one.
In this case, you disagree. But how could FFDL possibly know which one you consider 'correct' for any given story?
I think you need to take it up with the author and ask if they can list the two series the other way around.
This story by the same author shows that the order is not forced by ID number or date created by AO3.