Hi team, 
We need to have some functionality after placing the order so we used "checkout_onepage_controller_success_action"  events to call observer. 
We have issue intermittently "Order is successfully placed but observer is not called"
Can you please help me out of this problem
Hi ,
We are also facing the same issue. Did you find any solution to this problem?
thanks
Are you using any 3rd. party modules for checkout success page?
I had the same problem and found that disabling "Firecheckout Custom Success Page" solved the problem.
I am facing the same issue, the observer did not execute intermittently, do we have any solution to it?