Unable to change Blueprint Child Variable values in Python

Using the Python function unreal.SystemLibrary.set_bool_property_by_name() to change the default variable values of a child Blueprint do not work as intended.

Tested in 4.20.3 (CL - 4369336), 4.21.1 (CL - 4613538), 4.22 (CL - 4670176)

1. Create a Blank Blueprint 
2. Create a Blueprint called BP_Parent
3. Enable the Python and Scripting Utilities plugin
4. Execute the attached Python script

Expected: The boolean variable VarBool would be set to True

Result: The value stays at False