Any stack trace ?
No stack trace is there. It is not showing any error. just dont show any of the portlets
I never had any report like that neither in the forums or in the professional support we provide.
Without more information, i cannot tell what's wrong :(
Next time it happens, check if you get the "bottom" of the HTML page (closing html).
Another thing to do would be to ask the browser for the HTML source. Sometimes interesting things are there that do not show up on the display.
Source is showing the page containing the header but shows that no portlet is coming to the browser.
It shows end of html tag as well. It dont show any of the portlet. Just showing header of portal page. This is what i am able to see on the page as well.
So browser is not hiding anything.
Sorry i've never experience that neither in production or testing.
What you can try to do it to have the portlet shown on errors, it would help you find out what's wrong.
To do so:
See section 6.2.2