Are brace layers supposed to affect interpolation in the preview area?

I’m working with a brace layers for the first time. Changes made to the brace layer don’t affect the interpolated instances in the preview area at the bottom of the edit tab. Is it supposed to work like this or is it a bug? I’m asking about the preview area at the bottom of the edit window, not the free floating panel in Glyphs 3. I’m using version 3073. Here’s a screenshot of what I’m doing.

The definition of brace layers is different than in Glyphs 2. You need to right click it in the layer panel and select “Intermediate”, than double click it and add the numbers in the popup.