Google Drive API: No Parents with drive.files.get - google-drive-api

Question

I am using the Google Drive API. I can get a list of files with the drive.files.list API method. Here is the result of a call to this method:
{
"files": [
{
"id": "1yLJFT2bHhsz1WxJX29mD9DiNz0vLDlBvzJf5GJCcboI",
"mimeType": "application/vnd.google-apps.spreadsheet",
"parents": [
"0Bwy7SlKkxnwQRld6RWljU0Y4TG8"
]
},
{
"id": "0Bwy7SlKkxnwQVXdBRmlPMGNoTmM",
"mimeType": "application/vnd.google-apps.folder",
"parents": [
"0B4jAnSzS-VxlZW9RcDJheU5FYW8"
]
},
{
"id": "0Bwy7SlKkxnwQRld6RWljU0Y4TG8",
"mimeType": "application/vnd.google-apps.folder",
"parents": [
"0Bwy7SlKkxnwQQndiQnYxbUF4SjQ"
]
}]
}
When I request individual files using the drive.files.get API call, I would expect to get the same results as shown in the list above. I do when I request the first and third file listed. For example:
GET https://www.googleapis.com/drive/v3/files/0Bwy7SlKkxnwQRld6RWljU0Y4TG8?supportsTeamDrives=true&fields=id%2CmimeType%2Cparents
Result:
{
"id": "0Bwy7SlKkxnwQRld6RWljU0Y4TG8",
"mimeType": "application/vnd.google-apps.folder",
"parents": [
"0Bwy7SlKkxnwQQndiQnYxbUF4SjQ"
]
}
This is identical to what is shown in the list. But for some reason when I request the second file in the list, the parents list is missing from the result:
GET https://www.googleapis.com/drive/v3/files/0Bwy7SlKkxnwQVXdBRmlPMGNoTmM?supportsTeamDrives=true&fields=id%2CmimeType%2Cparents
Result:
{
"id": "0Bwy7SlKkxnwQVXdBRmlPMGNoTmM",
"mimeType": "application/vnd.google-apps.folder"
}
No parents array. Can anyone explain this behavior? I assumed all files should have a parent.

Answer 1

If you haven't done yet, you may want to check if you have an access to the parent of your second file. As stated in Enabling Team Drives:
A parent does not appear in the parents list if the requesting user is a not a member of the Team Drive and does not have access to the parent.
In Behavioral differences, fields related to permissions and ownership are populated differently.