Base path for attachment summary view broken

We have a situation where we need a summary view (done as in glossary mode using the first letter of the last name) on an embed view display that lists people. This type of glossary filtering is a relatively common request.

We don't want to use page displays for a number of reasons, so this embed view is displayed within a node entity (as part of a paragraph type but that is likely unimportant.)

The key is that we need to be able to set a base path for the summary links and not let Drupal simply use the path of the first view page display (of which there is not one.)

Attachments are allowed on embed displays: #2886613: Allow Attachments on Embed Displays → so this does seem like necessary functionality.

The base path field in the contextual filter options says: "Define the base path for links in this summary view, i.e. http://example.com/your_view_path/archive. Do not include beginning and ending forward slash. If this value is empty, views will use the first path found as the base path, in page displays, or / if no path could be found."

When no base path is entered, the summary links fallback as expected to / which obviously won't work for us but doesn't throw an error.

When a base path is entered such as 'super-page' (no beginning or ending slashes), I would expect that the summary links would then use "super-page/[letter argument]". However, instead the view completely fails to load and throws the following error:

Symfony\Component\Routing\Exception\InvalidParameterException: Parameter "node" for route "entity.node.canonical" must match "\d+" ("s" given) to generate a corresponding URL. in Drupal\Core\Routing\UrlGenerator->doGenerate() (line 204 of /web/core/lib/Drupal/Core/Routing/UrlGenerator.php).

This error occurs both when using "node/[nid]" and when using the path alias of the node.