Courses.List displays course, but Courses.Delete says Course Unknown - google-classroom

Question

I am trying to delete all classes from Google Classroom using the API. I call Classes.List to retrieve the ID number of all classes, then pass this to Classes.Delete. However at this point I get a 'Requested entity was not found.' error message.
I am unsure how this returns in the List command but fails on Delete. Are there any prerequisites of the Delete command that I cannot see on the Google documentation?
Same happens on the 'Try This API' section of the Google website, so fairly confident it isn't a code issue.
$ch = curl_init();
curl_setopt($ch, CURLOPT_URL,
"https://classroom.googleapis.com/v1/courses");
curl_setopt($ch, CURLOPT_CUSTOMREQUEST, "GET");
curl_setopt($ch, CURLOPT_RETURNTRANSFER, TRUE);
curl_setopt($ch, CURLOPT_HTTPHEADER, array(
"Authorization: Bearer $token",
"Content-Type: application/json"
));
$response = curl_exec($ch);
curl_close($ch);
$response = json_decode($response, true);
foreach ($response['courses'] as $Course)
{
$VLEID=$Course['id'];
$ch1 = curl_init();
curl_setopt($ch1, CURLOPT_URL,
"https://classroom.googleapis.com/v1/courses/".$VLEID);
curl_setopt($ch1, CURLOPT_CUSTOMREQUEST, "DELETE");
curl_setopt($ch1, CURLOPT_RETURNTRANSFER, TRUE);
curl_setopt($ch1, CURLOPT_HTTPHEADER, array(
"Authorization: Bearer $token"
));
$response1 = curl_exec($ch1);
curl_close($ch1);
var_dump($response1);
echo "<br/>";
die();
}

Answer 1

This seems to be bug on Google classroom side. Please see issue logged in GC issue tracker for this around the same time this question was posted here and the issue creator also mentioned it could be regressed issue as same API was returning different number of courses earlier.
https://issuetracker.google.com/issues/134993210

Answer 2

I'm seeing the same problem in my automated test suite. As far as I can tell, some of the courses being returned from Courses.List is returning courses that have already been deleted. I can't do a Course.Get on the id's either, nor do they show in when browsing courses on the Classroom web page. I know it didn't used to do that because this test suite has been around for years, but I hadn't run it recently, so either there has been a regression somewhere on the Google side, or perhaps it just take a while for the delete to fully propagate. I know the distributed nature of some of these services sometimes manifests in (usually) short term inconsistencies.