*Steps to reproduce:*
# Create a behavior graph "SubGraph" (open it and close it so that it will generate the runtime graph)
# Create and open a blackboard asset
# Add a BehaviorGraph variable to the blackboard asset
# Create and open another behavior graph "Parent"
# Dock the blackboard asset window next to the behavior graph window
# Change to the behavior graph tab
# Add the blackboard asset to the "Parent" behavior graph
# In the project view, select "SubGraph"
# In the inspector, click on the "Regenerate Runtime Assets"
# Open the blackboard asset and observe the value of the BehaviorGraph variable

*Actual results:* The BehaviorGraph variable still references the subgraph

*Expected results:* The BehaviorGraph variable shows a missing reference

*Reproducible with versions:*
1.0.9

*Can’t test with versions:* 
1.0.8 (the regenerate button is not there)

*Tested on (OS):* MacOS

*Notes:*
* Notice that the behavior graph window shows a missing reference
* If you leave the blackboard asset window shown open, the blackboard will actually reference a missing variable