Unable to create user group with restrictions - "Document type permission key not found"

I am attempting to create a new user group with a set of read-only restrictions on a specific document type. I have configured the desired permissions as follows in the user group settings:

However, when attempting to save and create the new user group, an error message is returned. The full request/response data is included below.

Request:

{
  "alias": "hphEditor",
  "documentRootAccess": true,
  "documentStartNode": null,
  "fallbackPermissions": [
    "Umb.Document.Read",
    "Umb.Document.Delete",
    "Umb.Document.Create",
    "Umb.Document.Update",
    "Umb.Document.Unpublish",
    "Umb.Document.Publish",
    "Umb.Document.Duplicate",
    "Umb.Document.Move",
    "Umb.Document.Sort",
    "Umb.Document.PropertyValue.Write",
    "Umb.Document.PropertyValue.Read",
    "Umb.Document.Rollback",
    "Umb.Document.PublicAccess",
    "Umb.Document.CreateBlueprint",
    "Umb.Document.Notifications",
    "Umb.Document.Permissions",
    "Umb.Document.CultureAndHostnames"
  ],
  "hasAccessToAllLanguages": true,
  "icon": "icon-users",
  "languages": [],
  "mediaRootAccess": true,
  "mediaStartNode": null,
  "name": "HPH Editor",
  "permissions": [
    {
      "$type": "DocumentPropertyValuePermissionPresentationModel",
      "userPermissionType": "document-property-value",
      "documentType": {
        "unique": "953b1571-10c7-49cd-8b82-ba986ea1246b"
      },
      "propertyType": {
        "unique": "8a8ab2f8-2ce7-4053-8331-c30a820ab170"
      },
      "verbs": [
        "Umb.Document.PropertyValue.Read"
      ]
    },
    {
      "$type": "DocumentPropertyValuePermissionPresentationModel",
      "userPermissionType": "document-property-value",
      "documentType": {
        "unique": "953b1571-10c7-49cd-8b82-ba986ea1246b"
      },
      "propertyType": {
        "unique": "e4219315-3a62-482b-82b0-ec740a0e3636"
      },
      "verbs": [
        "Umb.Document.PropertyValue.Read"
      ]
    },
    {
      "$type": "DocumentPropertyValuePermissionPresentationModel",
      "userPermissionType": "document-property-value",
      "documentType": {
        "unique": "953b1571-10c7-49cd-8b82-ba986ea1246b"
      },
      "propertyType": {
        "unique": "7692e3e5-676c-40dd-8d7c-d3f864f0fc05"
      },
      "verbs": [
        "Umb.Document.PropertyValue.Read"
      ]
    },
    {
      "$type": "DocumentPropertyValuePermissionPresentationModel",
      "userPermissionType": "document-property-value",
      "documentType": {
        "unique": "953b1571-10c7-49cd-8b82-ba986ea1246b"
      },
      "propertyType": {
        "unique": "14969e3a-f8d8-414d-b852-9c5061c13961"
      },
      "verbs": [
        "Umb.Document.PropertyValue.Read"
      ]
    }
  ],
  "sections": [
    "Umb.Section.Content",
    "Umb.Section.Media",
    "Umb.Section.Forms",
    "Umb.Section.Translation"
  ]
}

Response:

{
  "type": "Error",
  "title": "Document type permission key not found",
  "status": 404,
  "detail": "An assigned document type permission does not reference an existing document type."
}

The document type does exist, as I am able to view it within Settings and create Content which uses this document type. Note the matching document type GUID both in the request data, and in the address bar of the settings view:

Are there any other reasons this message could be getting returned from the API?