Can’t work out why my intercom series is triggering 4 webhook triggers (n8n executions) for the same payload/customer (user a)

series:

n8n executions : 

bare in mind the final merge2 in n8n waits for both inputs then sends slack message.
all nodes set to execute once.
in the left panel you can see the webhook was triggered 8.11, 8.14, 8.16, 8.21 am

intercom webhook block stats

user a should only have triggered the webhook once