Lozenge macro is broken in latest versions of Confluence

Recently, lozenge macros (part of Adaptavist's Content Formatting plugin) pointing to URL's are broken.

Steps to reproduce

1. Add a lozenge macro to a page
2. Edit the macro and insert the URL of a page (e.g. https://<subdomain>.atlassian.net/wiki/display/PA/PA+Home)
3. Save

Expected results

The macro redirects to the linked page.

Actual results

The macro fails to render and displays a red warning icon with the following tooltip:

Unhandled element type '{http://www.w3.org/1999/xhtml}a'

Workaround

Inserting the targeted page title (as opposed to its link) works.