It’s possible I’m not understanding what you are doing, but setting a variable does not trigger any code execution, it just sets the variable. That’s it!
Here I set a member variable of an other blueprint, the “SomeEvent” could be when you press a button in a UMG widget.
And here I’m trying to execute “Do a thing” or “Do another thing” when “Should Do Something?” changes. But this will NOT work! The branch will not be automatically executed when the variable changes. The code in the picture below will ONLY execute when the event “SomeOtherEvent” is called.