Scott, this does look off:
<swimlane name="Content Providers">
<assignment actor-id="Content Providers">
<actor>#{bpm_assignees}</actor>
</assignment>
</swimlane>
The jPDL reader does not read that actor subelement, only the actor-id attribute. That #{bpm_assignees} expression should be the value of the actor-id attribute. This could be the reason why the "submitInEditing" task shows up in "show tasks" but in "show my tasks". Of course, Alfresco might be using a custom jPDL reader, but this is unlikely.