Export to Excel or Word Is Generating HTML Instead

If I export a filter to Excel or to Word the resulting download has an .xls or a .doc file extension, but in both cases the file contains HTML. Have I misconfigured something (content types?), or is the "Export Excel/Doc" function mistakenly hooked up to "Export HTML" instead?

I just want to export the contents of the filter. CSV would be fine too (and more portable).

Steps to repro:
1. From the Issues > Search For Issues page, obtain a list of issues.
2. Choose Export > Word or Export > Excel.
3. A file "Atlassian JIRA.xls" or "Atlassian JIRA.doc" will be downloaded.
4. The file will open in Pages or Numbers but will only show the raw HTML.
5. From terminal run "file Atlassian\ JIRA.xls" and observe that it reports "HTML Document Text".
6. Rename the file to "Atlassian JIRA.html" and open it in a browser.
7. Observe that it renders as a web page.

Expected behaviour: file should be in Excel or Word format.

(Jira 6.3 EAP, Chrome, OS X.)