StringIndexOutOfBoundsError when trying to display certain issue text

See JRA-3370 for a demonstration. The stacktrace is:

java.lang.StringIndexOutOfBoundsException: String index out of range: 328
at java.lang.String.substring(String.java:1441)
at com.opensymphony.util.TextUtils.linkURL(TextUtils.java:834)
at com.opensymphony.util.TextUtils.hyperlink(TextUtils.java:479)
at com.opensymphony.util.TextUtils.plainTextToHtml(TextUtils.java:1317)
at com.opensymphony.util.TextUtils.plainTextToHtml(TextUtils.java:1288)
at com.atlassian.jira.web.tags.Text2Html.doEndTag(Text2Html.java:26)
at /secure/views/issue/viewissue.jsp._jspService(/secure/views/issue/viewissue.jsp.java:872)
at com.orionserver[Orion/2.0.2 (build 11157)].http.OrionHttpJspPage.service(.:70)

The presence of any issue like this also breaks the RSS/Excel/Full content view for searches that happen to include it.