This bug is reported against the appropriate plugin at http://developer.atlassian.com/jira/browse/SQL-58, but since it is caused by a change in Confluence we should keep it open here until we're sure that we aren't going to revert the Confluence change to solve it.
Use wiki markup such as:
After switching to RTE andback this becomes:
Which is no longer a valid query.
This did not happen in 2.10.