@kueda just released this new search param, ident_taxon_id=
Which should show all observations that have an active ID of the taxon you enter. For example, this should show observations which have an active Dysdera crocata ID, a commonly misidentified spider.
https://www.inaturalist.org/observations?ident_taxon_id=68912
Caveat - this only applies to observations uploaded since yesterday. We have to reindex all observations for them to show up here, but using it now will give you an idea of how it works.