It seems that the airport generation does not discard the key "disused:aeroway" in the airport configuration management
ex:
- +52-001
- Bad runway (geometry too far from a rectangle) close to Langar Airfield at (-0.9033422518987344, 52.8908686164557) : Langar
- +54-004
- Bad runway (geometry too far from a rectangle) close to (-3.3232789352941174, 54.20208328235294) at (-3.3232789352941174, 54.20208328235294) : Millom
They both use "disused:aeroway= runway" where the area might not be a rectangle as it has become something else.