Daily email notifications sends empty mails

Summary of Bug

When using Confluence 4.0.5, daily email notifications regarding changes done in the last 24 hours are empty.

Steps to Reproduce

1. Set up a mail server with Confluence 4.0.5
2. Subscribe to daily updates
3. Do some changes, and wait for the daily email update (or run the job instantly from the Scheduled Jobs menu)
4. Check your mail inbox and see if the daily update mail have any contents

Findings

• This was tested using gmail.com as a mail server (using JNDI connection), and sending to ymail.com
• During first testing, the daily notifications work properly (there are contents in the mail). During next testing (done a few days later), the daily notifications are empty even though changes have been made.