Editing A Page with undefined links Can break the undefined links

Issue Summary

When editing a page that has undefined page links, the editor will sometimes cause the links to become malformed causing them to no longer function on the page when published.

Steps to Reproduce

Note: this behavior is intermittent and may be possible to reproduce in some scenarios, but will be more difficult in some than others.

• Create a new page and use the "how-to" template (the how-to template produces the most consistent results.)
• create a undefined page link anywhere on the page.
• Once the page is created and published, edit the page again immediately.
• You may or may not end up with a broken link.

Expected Results

• You always get a working link

Actual Results

Undefined Page Links Break.mov
The editor will try to interpret the undefined link, and will evetntually produce a "null" after the ".net" portion of the URL. The following javascript error will be present:

APIError: URL not supported
    at p.fetchData (https://confluence-v1.prod.atl-paas.net/master/10795.PHZ48FYX71.js:169:3404)

Workaround

Available workarounds are:

• recreate the undefined page link by hand
• revert the page to a previous version
• reload the editor before publishing can sometimes result in the link loading properly.