bug: ES Router forms incorrect link for creating new discussion or linking to discussion

We have our ES Groups in the menu item with the URL <root>/groups. It was reported that when one was within a group viewing the list of discussions, clicking on any given discussion was returning one to the page that lists all groups. Further, the "New Discussion" button was also taking one to the list of groups.

In these cases I saw the formed links duplicating groups/ within the url. For example, to create a new discussion the URL would look like <root>/en/groups/groups/257-healthnet/27-discussions/create . My solution, to get the pages working again, was to override the layout files and add code to capture the generated link and remove any redundant "groups/" before echoing the link to the anchor tag. All works when that duplicate "groups/" is removed from the link.
-- generated link that fails: <root>/en/groups/groups/257-healthnet/27-discussions/create
-- fixed link that works: <root>/en/groups/257-healthnet/27-discussions/create

My client does not want me to grant login access to their site, plus I have already fixed this problem through overrides, so the best I can do is report this issue with the detail I just provided. The errant link is being generated by the ES::router.