Hi there,
Experienced the same issue with nested collectionTypes.
For Rest API, the solution is indeed to use ?populate=*
For GraphQL the solution is to add this to your gatsby-config:
{
name: ‘article’,
endpoint: ‘api/articles’,
api: {qs: {populate: ‘*’}}
}
After this, restart your server and it should work.
Let me know.
Kind regards, Jeroen