Some Phytomyza tiarellae observations appear only in "Unknown" taxa search, others only in "Insects"

Phytomyza tiarellae is an insect, but some observations of it appear in an search filtered for unknowns:
https://www.inaturalist.org/observations/identify?quality_grade=needs_id%2Cresearch&iconic_taxa=unknown&taxon_id=349464&place_id=any

While other observations of the same organism appear only in the search filtered for “Insects”
https://www.inaturalist.org/observations/identify?quality_grade=needs_id%2Cresearch&iconic_taxa=Insecta&taxon_id=349464&place_id=any

In both cases the taxon ID number is the same, and appear in the same spot in the taxon tree.

Some other similar cases among these:
https://www.inaturalist.org/observations?hrank=kingdom&iconic_taxa=unknown&place_id=any&verifiable=any&view=species&without_taxon_id=131236,67333,151817

Reindexing the observation (e.g. by voting “yes” next to “evidence of organism?”) seems to fix the Phytomyza tiarellae ones.