I have a dynamic number of pdf attachments as input from an adaptive form, and would like to merge all attached pdfs into a single pdf using DDX, then have it send separately with the Document of Record with the Send Email step. However I encountered an issue with the Send Email step with the following:
Caused by: com.adobe.granite.workflow.WorkflowException: GetPropertyValue failed as value corresponding to VARIABLE:attachments for type class java.lang.Object is NULL
The DDX is as follows:
<DDX xmlns="http://ns.adobe.com/DDX/1.0/">
<PDF result="Attachments.pdf">
<PDF source="fileAttachment"/>
</PDF>
</DDX>
Input map for invoke ddx:
The "attachment" path matches the output attachment folder of the adaptive form

Output map:
The output document is saved into the "attachments" document variable

Send Email step with Document of Record and attachments document:

I am unsure why the value for attachments is NULL. Any help on this is appreciated, thank you!
EDIT - testing workflowuser's process:
The following is the dynamic table with file attachments. The ordering is PDFs 1,2,3,4, but the resultant PDF from the process gives ordering 2,3,4,1.
