When i try to get data using the JSON API module, the field parent is always empty even if a term hierarchy exists.
For example, for a request to http://mysite.local/jsonapi/taxonomy_term/my_vocabulary/1a2a1fc1-b6d8-40be-a482-766ccab4aed1?_format=api_json&include=vid,parent, part of the response is the following one.
"parent":{
"data":[
]
},
How can I fix it?