When accessing most functions of Cornerstone, we are redirected to the following page:

Clicking “launch” will successfully launch Cornerstone, but will redirect to the page editor for the home page. You then have to manually navigate to the function/page you were attempting to access. This is true when accessing any part of the “X” menu in WordPress except for Validation or Settings, or when clicking “edit with Cornerstone” on an individual page. Investigating links that should direct to a specific part of Cornerstone, it appears that “cs-launch=1” is appended to all links (so the link to edit page ID 12 now becomes /?cs-launch=1&cs_route=content/12 instead of /x/content/12, the link to access “Theme Options” now becomes /?cs-launch=1&cs_route=theme-options where I typically see /x/theme-options, and so on).
I have disabled all plugins except Cornerstone with no change in behavior, and have duplicated this on multiple computers/browsers. The website does not have caching enabled, and permalinks are set to a custom structure of /index.php/%year%/%monthnum%/%day%/%postname%/, but it has been working with that structure previously.