Major Description
The force edit link contains an extra }, appended after the editor parameter, which causes it to not find specified editor and fail to load the page, something like:
/xwiki/bin/edit/Sandbox/Test?editor=wiki%7D&force=1
To reproduce, try to edit a page (picking a specific editor from the menu) while someone else has it locked. You'll get the message, and when clicking the "Click here to force editing" link, a page will be loaded with no editor in it.