linking @tiwane’s comment: https://forum.inaturalist.org/t/top-identifier-but-ive-made-no-ids-of-that-taxon/4930/3
OK, after consulting with Ken-ichi, it’s not a bug but intended behavior.
“The Identifiers tab in Obs Search shows the people who have added identifications to observations in the current search, not people who have added identifications of the taxon filtering the current obs search. I am fairly sure that was intentional, as obs search could have multiple filters applied to it that may or may not have anything to do with taxa”
(emphasis mine)
I don’t see how a filter of a taxa could ever not have anything to do with taxa, but if you are going to request this feature, how would you work around this issue?