Content Type Inherited column missing

Question

I have a a few content types defined at the tenant level (via Sharepoint admin) with some inheritance. Basically the structure is this,

Base Content Type

Field A

Field B

Field C

Child Content Type (inherits from Base)

Child Field D

Child Field E

<Inherited fields from Base>

For some reason after adding the content types to a Sharepoint Online document library, one of the columns has disappeared which should have been inherited. It does not make any sense as it is working in other SPO sites. How can I go about diagnosing this? I've tried creating a new Document Library within the same site and the same happens.

If I view the content type from the modern interface at the site level and compare the UUID to the ID at the Tenant level, both match. They should be the same type.

Thanks

Answer 1

Left image is at the site level, 'WFM Number' is missing. Right is the view from Sharepoint Admin at the tenant level, 'WFM Number' is there and visibly from the parent type 'Engineering Document' .

I can also see in both views, the API to retrieve the columns is roughly the same, it is 'there' , but something is stopping it being displayed,

{
    "@odata.etag": "\"1\"",
    "allowDeletion": true,
    "canBeDisplayedInEditForm": true,
    "columnGroup": "Tutis Columns",
    "columnValidation": {
    },
    "customFormatter": "",
    "description": "",
    "displayName": "WFM Number",
    "enforceUniqueValues": false,
    "eTag": "\"1\"",
    "filterable": true,
    "hidden": false,
    "id": "e207699f-76ab-41a1-a342-9dd922dbc4be",
    "indexed": false,
    "isDerivedType": false,
    "name": "WFM_x0020_Number",
    "number": {
        "decimalPlaces": "automatic",
        "displayAs": "number",
        "maximum": 1.7976931348623157e+308,
        "minimum": 0
    },
    "pushDownChanges": false,
    "readOnly": false,
    "reorderable": true,
    "required": false,
    "sealed": false,
    "shouldShowInDisplayForm": true,
    "shouldShowInEditForm": true,
    "shouldShowInNewForm": true,
    "shouldShowInVersionHistory": true,
    "showInFilterPane": "auto",
    "sortable": true,
    "type": "number",
    "typeDisplayName": "Number",
    "typeName": "Number",
    "valueType": "Double"
}

Thanks