Validation error on extensible binding

[Pete]

When trying to validate an Observation.code (shown below) against the StructureDefinition at http://hl7.org/fhir/us/mcode/StructureDefinition/mcode-tumor-marker-test (which has an extensible binding) I'm getting an error Unable to validate code http://ncimeta.nci.nih.gov#CL1643220 - No codes in ValueSet belong to CodeSystem with URL http://ncimeta.nci.nih.gov. This is on HAPI 8.0.0. We'd been on 6.4.0 previously and this was return as a warning instead of an error (as we'd expect).

{
    "resourceType": "Observation",
    "meta": {
        "profile": [
            "http://hl7.org/fhir/us/mcode/StructureDefinition/mcode-tumor-marker-test"
        ]
    },
    "code": {
        "coding": [
            {
                "system": "http://ncimeta.nci.nih.gov/",
                "code": "CL1643220",
                "display": "ctDNA Tumor Fraction"
            }
        ],
        "text": "ctDNA Tumor Fraction"
    },
    "valueQuantity": {
        "unit": "tumor-fraction",
        "value": 22,
        "extension": [
            {
                "url": "http://hl7.org/fhir/StructureDefinition/originalText",
                "valueString": "22%"
            }
        ]
    },
    "status": "final",
    "category": [
        {
            "coding": [
                {
                    "system": "http://terminology.hl7.org/CodeSystem/observation-category",
                    "code": "laboratory"
                }
            ]
        }
    ],
    "subject": {
        "identifier": {
            "value": "bogus-patient"
        }
    },
    "effectiveDateTime": "2023-01-01T00:00:00+00:00"
}

[Pete]

Anybody? It looks like the binding check is not working for other StructureDefinitions either