title: PayPal REST API cancel URL called after payment executed
body: <p>I have a strange problem, I'm trying to figure out.</p>
  
  <p>I'm using PHP and REST API.</p>
  
  <p>This is the scenario:</p>
  
  <p>1) Users press the checkout button</p>
  
  <p>2) Payment is approved</p>
  
  <p>3) Payment is executed</p>
  
  <p>4) User is redirected to the completed purchase page</p>
  
  <p>5) Few seconds later, Cancel URL of the transaction is called (like when users clicks on Cancel and return to merchant button, instead of approving the payment). </p>
  
  <p>Out of about 100 transactions I had 3 wich manifested this way on all 3 the payment was actually made, and the funds where available. I have checked the server access log files and 2 of them were using ios 9.3.1 and one was an ios 9.2.1. How is this possible?</p>
  
  <p>My guess is that they somehow hit the back button and then the cancel button, can this be the case?</p>
  
  <p>My cancel URL contains a script which sets the order status to canceled, should I adjust the script to only set the status to canceled if the order wasn't previously executed. </p>
  
  <p>Can anybody still cancel the payment AFTER I have executed the payment?</p>