column – SPFX – Update list with a new field fails

I’m trying to deploy a new field (column) to a custom list that has been deployed using a SPFx Extension. The field gets added to the site, but it does not get added to the ContentType.

I’ve been following this guide however I’m still unsuccessful in updating the list.

I’ve added elements-v2.xml:

<?xml version="1.0" encoding="utf-8"?>
<Elements xmlns="http://schemas.microsoft.com/sharepoint/">
    <Field ID="{504d394b-c0a2-4937-b9ad-b9b7b9ad2ceb}"
        Name="TestField"
        DisplayName="TestField"
        Type="Text"
        Required="FALSE"
        Group="MyColumns" />
</Elements>

And upgrade-actions-v2.xml:

<VersionRange
    BeginVersion="2.0.0.0"
    EndVersion="2.9.9.9">
    <ApplyElementManifests>
        <ElementManifest Location="2aee3d9c-ffbe-48b4-9960-2290c09f8fa7elements-v2.xml" />
    </ApplyElementManifests>
    <AddContentTypeField 
        ContentTypeId="0x010042D0C1C200A14B6887742B6344675C8B"
        FieldId="{504d394b-c0a2-4937-b9ad-b9b7b9ad2ceb}"
        PushDown="TRUE"/>
</VersionRange>

package-solution.json is updated accordingly:

        "version": "2.0.0.3",
        "assets": {
          "elementManifests": (
            "elements.xml",
            "ClientSideInstance.xml",
            "elements-v2.xml"
          ),
          "elementFiles": (
            "schema.xml"
          ),
          "upgradeActions": (
            "upgrade-actions-v2.xml"
          )

And the new column “TestField” is referenced in schema.xml

        <ViewFields>
          <FieldRef Name="Namn"></FieldRef>
          <FieldRef Name="Roll"></FieldRef>
          <FieldRef Name="E_x002d_mail"></FieldRef>
          <FieldRef Name="Projektomr_x00e5_de"></FieldRef>
          <FieldRef Name="B_x00f6_rjar_x0020_p_x00e5__x002"></FieldRef>
          <FieldRef Name="Slutar_x0020_p_x00e5__x0020_proj"></FieldRef>
          <FieldRef Name="Bild"></FieldRef>
          <FieldRef Name="TestField"></FieldRef>
        </ViewFields>

If I go to “Settings” -> “Site Columns” I can see that the column is added to the site

enter image description here

But if I go to the ContentType it looks like this:
enter image description here

The field is added to the site, but it’s not added to the contentType. I can get it to work by removing the column “Testfield” from the site, increment the version in “package-solution.json”, deploying, and upgrading app on the site. That way the “Testfield” is added to the site again but this time it’s associated contentType from some reason.

To summarize the issue:
Updating the list with a new field/column fails because the field/column does not get added to the ContentType that is associated with the list.

Am I missing something in order to get the field added to the ContentType? Looking at the guides/reference for <AddContentTypeField> I cannot see that I’m doing something wrong.