I have a workflow that kicks off a new workflow as its last step.

When it kicks that new workflow off, I want it to complete the current workflow, however it stays open until the next workflow is complete, even if it is asynchronous

This is the correct behaviour Since you have workflow activity in the last step which is in sleeping state and which waits for the child wf to execute so the workflow stays open even if it is asynchronous.

Thanks,

Santosh Kumar