GeoNetwork cannot harvest 'metadataUrl' from WMS 1.3 GetCapabilities

I am trying to harvest a WMS v1.3 layer from GeoServer v2.17
using GeoNetwork v3.4 & v3.10.

I’d like the GeoNetwork to read the URL from ‘metaDataUrl’ in WMS GetCapabilities response

i.e. I have ticked ‘Import record for each layer using MetadataURL attributes’ in the ‘OGC Web Services’ harvester

The geoserver does output ‘metadataUrl’ in its WMS 1.3 GetCapabilities response,
but the geonetwork does not recognise it:

<Layer queryable="1" opaque="0">
...
    <MetadataURL type="19139">
        <Format>text/xml</Format>
        <OnlineResource xlink:type="simple" xlink:href="https://geonetwork.blah.org/geonetwork/srv/api/records/12345_435454_234343_343_23/formatters/xml"/>
    </MetadataURL>

The logs say:

No metadataUrl attribute found for layer ‘blah’
Failed to load metadata document for layer ‘blah’. Error is: ‘null’

What kind of ‘metadataurl’ XML does the GeoNetwork expect in GetCapabilities ?
Is there an example I can get hold of?

<Layer queryable="1" opaque="0">
...
    <MetadataURL type="TC211">
        <Format>text/xml</Format>
        <OnlineResource xlink:type="simple" xlink:href="https://geonetwork.blah.org/geonetwork/srv/api/records/57628_453_9406_3211_5/formatters/xml"/>
    </MetadataURL>