The creation of sub-projects does not mean they will be left out of your shared Viewkeys for your Parent Projects.
To include a sub-project within your parent viewkey, simply enable this from your Settings.
To do this, click on the 3-dots menu -> Project Settings, then check "Display Sub-Projects in Parent Projects"
This feature is helpful if you are looking to include multiple sub-projects within a single viewkey.
We hope you find this helpful! If you need any further assistance, please contact us and we'll be more than glad to help you out.