"More about groups" link broken

Using Atlassian 5.8.10
Visit this link: /admin/users/browsegroups.action?searchTerm=&resultsPerPage=10&startIndex=0
Right nav contains a link titled "More about groups" to this URL: https://docs.atlassian.com/confluence/docs-58/Global+Groups+Overview

ACTUAL: "Page Not Found", attempts to refer you to docs-56 and below.
EXPECTED: Some actual page, no "not found" error, not a search results screen.

Maybe link directly to docs-56 if you don't care to write new docs.