I have a Form that upon submittal:

1. Calls a Workflow & waits to hear from Workflow before proceeding
2. Workflow sends back DBNull values so that a table is emptied out
3. Forms calls the Workflow again & waits to hear from Workflow before proceeding
4. Workflow passes back the values to populate the table

Here is the process diagram for those who are more visual.

I am not looking to change the process, as it currently takes two separate Workflows to clear out a table and then repopulate it.  The issue I have found is that the first time the Workflow runs, it correctly passes the "bp instance name", which can be seen blurred out in the orange box below.  

When the Forms process then calls the workflow a second time 2s later, the "bp instance name" is blank, as seen below in the orange box.

I've already found a work-around for this issue but am curious if anyone has noticed this and/or if anyone knows why this happens if you call two workflows back-to-back