Targeted message activates another receiver

Question

Version : Appian 20.3. 
 
 I have a process with 2 Event Receivers : "External_Escalaion" & "Escalation". 
 I have a User Input node which escalates, sending a message to destination called "External_Escalation" (in the same process). 
 I would expect to receive the message only on the "External_Escalation" node, however it triggers 
 the other as well. 
 
 Any clues ?

Dave Lewis · Answer

I know why! Appian does not initiate a process with a start form until you complete the start form. It actually comes highly recommended that you make as many processes with start forms as you can for this reason. It really, really saves your engines not having to run until the process is really going. 
 In your case, it prevents the escalations from doing anything until the process is started running, which would be after the start form completes. That's the whole problem, that whoever won't fill out (or can't fill out) the start form, so this process is in limbo. 
 The solution is to break with best practice and instead make this PM with no start form. Just chain directly into a User Input Task as the first node. Then stick the form that would have been a start form directly in there. If it's not a Site action, users will have absolutely 0 change to their experience. If you're using a Site, you unfortunately NEED a start form, so you may want to consider a very simple start form like "Ready to get going? Click here!" and a single button. In your case you want it to be basically impossible for your users to have not made it past the start form and into the main part of the form, where the escalations can help. 
 You also might want to consider configuring those End Nodes to Terminate. My project has had no end of woes from processes that like to hang out forever, even after all the nodes are executed. Best practice from Appian is all PMs should contain at least one Terminate node.

Peter Lewis · Answer

I echo David's point that you would probably have better luck with a different design pattern. There really isn't a need to send a process message within the same process because you can just set up the logic directly in your process to account for it. For instance, if you set up your process like this it should result in the same behavior: 
 
 Then you would only need a single message (that receives a message external to the process). To be honest, I actually have never seen someone try to send a message to another node in the same process - In general it's best to limit usage of process-to-process messaging if there is another design pattern because it's difficult to troubleshoot and easy to create performance issues when using it.