Attempting to copy a page in Confluence fails silently

Summary

Users experience a silent error when trying to copy a page. No dialog is shown.

Steps to Reproduce

1. Copy page
2. Try to save the copy

Expected Results

Page saves as normal.

Actual Results

Page does not save, editor stays open. No errors displayed or logged.

Workaround

Remove personal labels (including favourites) from the page prior to copying.

Use this query to find out which users have favorited this page:

confluence=# select u.username from label l, content_label c, user_mapping u where c.labelid = l.labelid and u.user_key = l.owner and c.contentid = (select contentid from content join spaces on content.spaceid = spaces.spaceid where content.contenttype = 'PAGE' and content.title = '<PAGE TITLE>' and spaces.spacekey = '<SPACE KEY>');