Any resolution to this? After upgrading to 2.6.2 I’m now experiencing the same issue. I can confirm that it behaves this way using multiple clients (BlogJet and Live Writer) and using multiple API formats (WordPress, Blogger, Movable Type).
Definitely a problem with how xmlrpc processes posts as it works fine in the web-based editor. I do not have this problem using the same client (BlogJet) on any other blogs that are still running pre-2.6.2.
