The same process was executed twice

Here is my flow chart.
When the A node is finished, it will call call service, and execute the B node at the same time.
The problem is node A, which will be executed twice and send events.
Is there something wrong with my process?

Thanks

bpmn (12).bpmn (8.1 KB)

Where is code to trigger the event? In callService or Node A?
you should use exclusive gateway to depict the outgoing flow from node A. Since
the delegates in CallService is at two place(in subprocess and main process), it will be always called twice

Thank you for your quick reply.@ Abhinav_Kumar1
I hope A’s call service does not affect B UserTask… So I didn’t use a mutex gateway.
How should I draw my process?