Migrate paragraphs and nodes from 2 different SQL tables

Hello,

I'm migrating projects from a custom SQL database to a new project content type which contains paragraph fields.
I can import projects and paragraphs but I stumble on the way to link them together.

Using Drupal 8.5.2, Migrate Plus 4.0-beta3 and Migrate Tools 4.0-beta3.

I have 2 following SQL tables as a source:

Project table
+----------------+--------------+------+-----+---------+----------------+
| Field          | Type         | Null | Key | Default | Extra          |
+----------------+--------------+------+-----+---------+----------------+
| id             | int(11)      | NO   | PRI | NULL    | auto_increment |
| client_id      | int(11)      | NO   | MUL | NULL    |                |
| name           | varchar(100) | NO   |     | NULL    |                |
| comment        | longtext     | YES  |     | NULL    |                |
| contact        | longtext     | YES  |     | NULL    |                |
| updatedAt      | datetime     | NO   |     | NULL    |                |
+----------------+--------------+------+-----+---------+----------------+

Service table
+------------+--------------+------+-----+---------+----------------+
| Field      | Type         | Null | Key | Default | Extra          |
+------------+--------------+------+-----+---------+----------------+
| id         | int(11)      | NO   | PRI | NULL    | auto_increment |
| project_id | int(11)      | YES  | MUL | NULL    |                |
| title      | varchar(255) | YES  |     | NULL    |                |
| url        | varchar(255) | YES  |     | NULL    |                |
| comment    | longtext     | YES  |     | NULL    |                |
+------------+--------------+------+-----+---------+----------------+

Here is the service migration:

id: service
label: Service Providers
source:
  plugin: service
  keys:
    - 'id'
ids:
  id:
    type: string
process:
  field_name: title
  field_url: url
  field_comments: comment
  uid:
    plugin: default_value
    default_value: 1
  status:
    plugin: default_value
    default_value: 1
destination:
  plugin: 'entity_reference_revisions:paragraph'
  default_bundle: service_provider

And my project migration:

id: project
label: Projects
source:
  plugin: project
  keys:
    - 'id'
ids:
  id:
    type: string
process:
  type:
    plugin: default_value
    default_value: project
  title: name
  field_client:
    plugin: migration_lookup
    migration: client
    source: client_id
  field_service_providers:
    plugin: iterator
    source: service
    process:
      temporary_ids:
        plugin: migration_lookup
        migration: service
        source: project_id
      target_id:
        plugin: extract
        source: '@temporary_ids'
        index:
          - '0'
      target_revision_id:
        plugin: extract
        source: '@temporary_ids'
        index:
          - 1
  body: comment
[...]
destination:
  plugin: 'entity:node'
migration_dependencies:
  required:
    - user
    - client
    - service

Unfortunately field_service_providers doesn't get populated.
Yesterday I spent the whole afternoon to google and try dozens of examples without any luck.

Any help would be greatly appreciated! :)