Why does subform detect the wrong activity?

I discovered what appears to be a bug with the Bean Shell Form Binder in a subform.  To make a long story short, the hash variables for activityId, activityName, and activityDefId contain the wrong values when access from the Load Binder of a Section in a Subform.  

Scenario:

1. Process that asynchronously spawns 3 activities
2. A subform with a Bean Shell Binder as the Load Binder on the first Section
3. Version: 6.0-BETA4 - build b34bace ( I haven't tested this in other versions)

Example: Sample app that I created to demonstrate the problem.  

Activity 1, 2, and 3 are triggered when the process starts

Activities 1 and 2 are mapped to a form which has a subform .  The subform contains a Bean Shell Binder as the Load Binder on the first Section and displays the values of the activityId, activityName, and activityDefId hash variables in a text field.  Notice in the following example, that when I click on Activity 1, the header correctly indicates Activity 1, but the subform reports that the hash variables point to Activity 2. 

Activity 3 has been mapped directly to the form that has the Load Binder. In other words, there's no subform at play.  When I open Activity 3, the form correctly reports Activity 3 in both the header and hash variables.  

Of course this is just a sample application to demonstrate the problem. I encountered it while developing a more complicated application in which I need to be able to detect the current activity from within the subform Bean Shell.  Am I doing something wrong or is this a bug?

APP_demoHashVarBug-1-20171127142702.jwa

I've attached a sample application that demonstrates this problem.