Extension information not added to Tenant wide extensions

What type of issue is this?

Question

What SharePoint development model, framework, SDK or API is this about?

💥 SharePoint Framework

Target SharePoint environment

SharePoint Online

What browser(s) / client(s) have you tested

• 💥 Internet Explorer
• 💥 Microsoft Edge
• 💥 Google Chrome
• 💥 FireFox
• 💥 Safari
• mobile (iOS/iPadOS)
• mobile (Android)
• not applicable
• other (enter in the "Additional environment details" area below)

Additional environment details

SPFx version: v1.18

Issue description

I have a solution containing 2 webparts and an extension. For some reason the extension isn't deployed tenant wide, the entry doesn't get added to the tenant wide extensions list (/sites/AppCatalog/Lists/TenantWideExtensions).

I don't see anything wrong with my configuration.

/sharepoint/assets/ClientSideInstance.xml:

<?xml version="1.0" encoding="utf-8"?>
<Elements xmlns="http://schemas.microsoft.com/sharepoint/">
  <ClientSideComponentInstance
      Title="Productname"
      Location="ClientSideExtension.ListViewCommandSet"
      ComponentId="GUID from extension's manifest"
      Properties=""
      ListTemplateId="101">
  </ClientSideComponentInstance>
</Elements>

config/package-solution.json:

{
  "$schema": "https://developer.microsoft.com/json-schemas/spfx-build/package-solution.schema.json",
  "solution": {
    "name": "productname",
    "id": "GUID",
    "version": "3.1.3.0",
    "includeClientSideAssets": true,
    "skipFeatureDeployment": true,
    "isDomainIsolated": false,
    "features": [
      {
        "title": "Productname",
        "description": "Productname",
        "id": "GUID",
        "version": "3.0.0.0",
        "assets": {
          "elementManifests": [
            "ClientSideInstance.xml"
          ]
        }
      }
    ]
  },
  "paths": {
    "zippedPackage": "solution/productname.sppkg"
  }
}

I do see the ClientSideInstance.xml included in the resulting sppkg.
I do have to "deploy to all sites" option checked when updating the extension.

But why doesn't it get applied? Am I missing something?