I came across this recently: https://www.inaturalist.org/taxa/742760. Article 27 of the ICZN states that diacritic marks are not to be used in scientific names. The ‘source’ link is broken for this taxon, but the 2018 checklist has the correct name (http://www.catalogueoflife.org/annual-checklist/2018/details/species/id/34d4c16dd0d39e4e5ebf4eca7a63d2cd), and it does not appear to have been updated since 2011. So I’m not sure what happened here.
At any rate, is there a way to prevent iNaturalist from accepting scientific names with diacritic marks?