The Nominatim QA tool added a new layer “Suspicious addr:state value”

• If addr:state is the same addr:province. Depending on country addr:province might not be needed
• If addr:state is the same as the country code
• if addr:state is the same as the country name (in any language)

https://nominatim.org/qa/#map=3.52/34.84/5.81&layer=addr_state_not_country

The layer is updated every day.

Give it a go. But not USA and Canada because I was too eager and made many edits today already.