Listing user collaborations

I can't find documentation for an endpoint listing user collaborations. The request below seems to work fine, with an exception of setting `fields` query parameter. The result doesn't include the `item` and other basic fields.

```

curl --request GET \
  --url 'https://api.box.com/2.0/users/me/collaborations?fields=item&status=accepted' \
  --header 'Authorization: Bearer ...' \
  --header 'as-user: ...'

```

Could this be a bug?