Getting random generic error with Apps Script

Question

The following code works 99% of the time, but every once in a while fails with this rather generic error:

"GoogleJsonResponseException: Backend Error at warmCache (WarmCache:225)"

var page = AdminDirectory.Groups.list(
{
  customer:   'my_customer',
  maxResults: 30,
  pageToken:  pageToken
});

Has anybody else seen this?

Thanks for any tips or pointers.