title: What is the expected behaviour when using a differential query regarding how many times you may request a page and the page is empty?
body: <p>What was the user doing - I am trying to implement Azure AD Groups synchronization in my app as described at <a href="https://developer.microsoft.com/en-us/graph/docs/concepts/delta_query_groups" rel="nofollow noreferrer">https://developer.microsoft.com/en-us/graph/docs/concepts/delta_query_groups</a>.</p>
  
  <p>However, when implementing the step described under nextLink response, where it says "The response contains a nextLink and another skipToken, indicating there are more groups available. You continue making requests using the nextLink URL until a deltaLink URL is returned in the response.", I am experiencing that a lot of empty page responses containing nextLink are returned by the API before finally receiving one that contains a deltaLink. The fact that the pages are empty is expected since there are no changes in the groups. The largest number I have seen was 15, but it's typically around 4-5 pages.</p>
  
  <p>Is this behavior expected?
  Here is an example of this situation, the following is a list of Request-ids and timestamps:</p>
  
  <p>Initial request to /delta
  date: Thu, 11 Jan 2018 07:14:32 GMT
  request-id: 4ccf6e1e-e151-491c-a24d-b2d8c143ad4a</p>
  
  <p>Request 1 (following nextLink from previous):
  date: Thu, 11 Jan 2018 07:14:32 GMT
  request-id: a55e2271-1703-47ec-b052-d7169d017dbb</p>
  
  <p>Request 2 (following nextLink from previous):
  date: Thu, 11 Jan 2018 07:14:32 GMT
  request-id: 4c40e7b2-cd1a-4871-b452-e22f3dc5de03</p>
  
  <p>Request 3 (following nextLink from previous):
  date: Thu, 11 Jan 2018 07:14:32 GMT
  request-id: aa98732c-8635-45d0-99af-d3289a0c47b6</p>
  
  <p>Request 4 (following nextLink from previous):
  date: Thu, 11 Jan 2018 07:14:32 GMT
  request-id: cea81ae1-0437-4e96-9fe9-29bc193dffb4</p>
  
  <p>In this case, all requests return an empty list of changes ("values:" []). However, requests 1-3 all return a nextLink and it is only request 4 that finally returns a deltaLink.</p>
  
  <p>Is this the expected behavior?</p>