Unable to switch language from anything but English

Steps to reproduce:

1. Access the Language & Time screen (Server -> Server Manager -> Language and Time)
2. Change the language from English to (e.g.) French
3. Change the language from French back to English

Expected results:

• The language is changed to English

Actual results:

• An exception is display on screen an the language is not changed

HTTP ERROR 400

Problem accessing /server-locale.jsp. Reason:

Unable to parse form content

Caused by:

org.eclipse.jetty.http.BadMessageException: 400: Unable to parse form content at org.eclipse.jetty.server.Request.getParameters(Request.java:390) at org.eclipse.jetty.server.Request.getParameter(Request.java:1025) at org.jivesoftware.util.ParamUtils.getParameter(ParamUtils.java:52) at org.jivesoftware.util.ParamUtils.getParameter(ParamUtils.java:36) at org.jivesoftware.openfire.admin.server_002dlocale_jsp._jspService(server_002dlocale_jsp.java:145)

....

Caused by: org.eclipse.jetty.util.Utf8Appendable$NotUtf8Exception: Not valid UTF8! byte 74 in state 3
at org.eclipse.jetty.util.Utf8Appendable.appendByte(Utf8Appendable.java:253)
at org.eclipse.jetty.util.Utf8Appendable.append(Utf8Appendable.java:158)
at org.eclipse.jetty.util.UrlEncoded.decodeUtf8To(UrlEncoded.java:526)
at org.eclipse.jetty.util.UrlEncoded.decodeTo(UrlEncoded.java:577)
at org.eclipse.jetty.server.Request.extractFormParameters(Request.java:547)
at org.eclipse.jetty.server.Request.extractContentParameters(Request.java:471)
at org.eclipse.jetty.server.Request.getParameters(Request.java:386)
... 50 more