This annoyance may be a feature or bug, I am not sure.
If you use an undefined variable name in an Assign activity, the value changes on its own.
This causes a bit of confusion once the variable name is defined, because now the value may have unexpectedly changed.
To illustrate for a c# windows project:
Create assign activity using an existing boolean variable: (i.e. variable: checkpoint, value: true)
Change toe variable name to a different undefined variable name and press enter.
You will see the true value change to True (upper case T).
When you put back the existing variable, the code is flagged as an error (the name True does not exist in the current context). This can be fixed by changing True to lower case true.
I believe the value field should remain unchanged.
Are you trying to create boolean variable in the assign activity? So it can either have 2 values"True" or “False”. I hope that why if you create a new boolean variable its setting the default values as “True”