Why Rounded Font filter works differently as a parameter?

When using Rounded Font filter as a parameter at export, the result is like this:

Screenshot 2024-12-18 at 14.02.57

And when used through the Filter menu, the result is like this:

Screenshot 2024-12-18 at 14.03.21

Why are they different? The latter is actually what I want. How can I make it work as a parameter?

Can you show the paths of your E?

Sure. (Those handles are needed because this is a variable font.) it makes no difference if I expand the outlines.

Screenshot 2024-12-18 at 17.23.02

the round font is doing less to give more control. Add a “Round Corner” filter.