We just wanted to know whether the syntax to fetch the queue owner 'Owner:Queue.QueueName='Duplicate Leads'' (in formula field)still works fine in salesforce becuase it seems like this is not working in our functionality.

When I am changing Lead Owner with a custom profile and checking "Send Notification" flag , system is giving error. If I am not selecting Send Notification flag then no error is coming. On Lead trigger trigger there is a part of code that update the User object. When I am commmenting these lines of code. Everything working as expected.