Validation email does not contain full date

The validation email does not contain the full date and time the account was requested. It says:

This account was requested on Tue

The problem seems to be the comma in the application.timestamp property (in the security.properties file):
application.timestamp=EEE, d MMM yyyy HH:mm:ss Z

If I remove the comma, then the email correctly says:

This account was requested on Tue 26 Dec 2006 13:07:48 -0700