Inbound Action - Assign only works if Assignment Group is included

[Tamara11]

We have an Inbound Action configured to create incidents from incoming emails and it's working well unless we attempt to use assign:without also using assignment_group:.    

So our choices are to not use assign or to include the assignment group if we do.  As you can guess, our users aren't super fond of that option.

If I look in the logs, I can see that it tries to create an incident, but the incident isn't anywhere that I can find.

Example log entry: Information Processed 'Create Incident', created incident :INC0012021

Here is the relevant portion of my script.  It works, as long as assignment_group is present.

if(email.body.assign != undefined){
	if (email.body.assign.indexOf('<mailto:')){
		var assignsplit = email.body.assign.split('<mailto:')[0];
		gs.log("email body assign: " + assignsplit);
		current.assigned_to = assignsplit;
	} else {
		gs.log("email body assign: " + email.body_text.assign);
		current.assigned_to = email.body_text.assign;
	}
}

if(email.body.assignment_group != undefined){
	gs.log("assignment : " + email.body.assignment_group.trim());
	current.assignment_group.setDisplayValue(email.body.assignment_group.trim());
}

I've been tinkering with the Dictionary settings as I suspect they might be the culprit, but so far nothing I've tried has provided resolution.

Does anyone have any suggestions?

[Tamara11]

@Saurav and @Allen Andreas,

Thank you both for your help looking at this.   After I took my focus off of what I might be doing wrong in my script, I did find a variety of Business Rules and Scripts that involve Assignment Group and Assigned To coordinated with Business Services and Service Offerings that were implemented long ago and are used by another process.  

I'll have to refine them once time allows, but for now I'm just going to add a query to the group table in my "assign:" block and force the assignment group if it's not provided.

Thanks for getting me pointed in the right direction.