Is possible to create a specification using the following API: https://developers.vtex.com/docs/api-reference/catalog-api#post-/api/catalog/pvt/specification

The field "FieldGroupId" is the ID of the group of specifications that contains the new specification. However, when the group belongs to a parent category, not the category used for creating the specification, the error Field Group not found in the category is returned.

1. Create a group category on a Parent category
2. Use the API above to create a new specification on a child category
3. Fill the field FieldGroupId with the groupId from the parent category
4. Check that the error appears.

Create the specification via UI, create the specification on the parent category or create a group on the child category to use.