I’ve searched through the discourse. The problem has arisen in years earlier, but the fixes are not clear with later versions of Sage due to differing files in lib directory.
As the image shows, when I set up a 3-level menu, the grandparent menu item is always .active, even when I select another non-related link.
The bug only manifests itself with 3 levels. If there are only parents & children, .active is appropriately removed when selecting an unrelated link.
Is there a workaround that I can use for v.8.5?