We have about 40 VF pages that our call center uses to collect information from our customers. Most of the pages use the "rerender" parameter to update the form being displayed. The questions that are asked vary depending upon prior responses.

We have been getting intermittent display of HTML code including the ViewState instead of the VF page when the rerender is invoked. I've been working with tech support for weeks, made several changes to the code but the problem persists. It has now occurred twice using Winter '11.

The failure occurs about 2 times per day across a group of 40 users so it is infrequent. It occurs in IE6, IE8 and Firefox 3.6.x. All users are on Windows XP. I have been unsuccessful in duplicating the problem and the users cannot make it happen at will.

Has anyone else experienced intermittent problems with rerender? Any ideas?

Thanks,

Vin