Page text editor become unavailable after copy / parse the symbole with either bullet list or numbered list

Here is the reproduction procedure:

1. Add the bullet list or numbered list.
2. type some text.
3. Click on "Insert >> Symbol", then select one symbol and add it into the line.
4. Change the line.
5. Select the first line, copy it then parse to the second line.
   We can observe that the text editor is not available any more and no text typing is accepted. Also, we can find the error message in the atlassian-confluence.log, if we use the "right arrow" in the test:

   2011-12-05 19:00:29,689 INFO [http-4405-2] [render.xhtml.migration.ErrorReportingV2Renderer] render Unable to render content on page ~admin:copy parse test
   Wrapping content in unmigrated wiki markup macro due to system error: The macro 'right arrow' is unknown.