title: Getting "This item is currently being modified" when testing purchases on iPad
body: <p>We have an app with many in-app purchases.
  Two days ago we started getting the following error message when testing purchases:
  "This item is currently being modified. Please try again later" and then the purchase fails.
  This happens 90% of the time.</p>
  
  <p>We thought there was something wrong with the test user we were using. But using another user account also produces the same issue.</p>
  
  <p>Has anyone ever encountered this problem?</p>