TinyMCEBuilder must use absolute URIs for embeddings like images because the resulting page content "moves around" in the site hierarchy and the links break.
Permalinks must be absolute. The "navigate to permalink" link in the editor broke.
Local redirects must be relative to the site root
Site config needs to fix up a root that doesn't end in a slash. That's the most fundamental issue.
There are a few fixes here for #665