I thought it would be helpful to put it out there that there is a known issue with the latest SA release (6.5r4) and OWA 2007. There is nothing in the release notes about this but there is a PR opened (527943) and we've been told a patch is expected in June.
The behavior is users receive a 404 from OWA when trying to sent a message with a certain length. The 404 is coming from the CAS server but gets passed through the SA into the OWA GUI.
We ended up rolling back and will make sure to test OWA from this point out in our lab.
I have no idea if OWA 2003 is affected since we're only running 2007.
http://kb.pulsesecure.net/KB17485 has been written for this issue and covers the root cause of the problem.
If you currently attempt to download 6.5R4 a warning pop-up appears with the following text:
If you are certain that you still wish to download, click the Continue Download button..."
FYI, OWA 2003 is affected as well...
We have to wait for the fix.