Is your AdditionalDriver attribute read/write for the user role you are logged in with? And do they have rights on the nano- or microflow as well? It looks like it should work from your screenshots.
If that's not the issue, have you tried debugging to see what happens in which case?
Yes AdditionalDriver attribute has read/write access for the user role. And they have rights on the microflow as well.
I have shared some images, Could you have a look into it