Email headers not showing on initial load in 1.7-rc4

[SKaero]

I tested with the account you send and was able to briefly see the problem, after switching the email to plan text all the headers showed up as normal and the problem happen again. I noticed that you have a larger number of plugins enabled. Can you try diabling all the plugin and see if the issues continues? My leading guess is that either a outdated plugin or conflict between plugins is causing the issue.