PhotoCollections.create cannot use custom_fields and parent_collection_id at the same time node.acs

Using node.acs, I have an API call to create a Photo Collection, which is a subcollection that requires a custom field:

ACS.PhotoCollections.create({
                    name: name,
                    custom_fields:{file_id:'test'},
                    parent_collection_id: type
                }, function(e) {
                    if (e.success) {
                        console.log(JSON.stringify(e));
                        res.redirect('/content');
                    } else {
                        console.log('Error:\n' +
                            ((e.error && e.message) || JSON.stringify(e)));
                    }
 
                });

It seems that if I include the parent_collection_id parameter the custom_fields parameter is ignored. If I run the same call with parent_collection_id omitted the custom fields are created without issue.

Any help appreciated!