... Blogmeister KenP offers good advice:
"The problem you're encoutering is because the site runs off of two parallel servers. Once in a while, one server will hand you a code and the other server will randomize a different code. We know it's a pain, and Ryan's working with our server tech on a way to resolve it. Meanwhile, my best advice is if you're writing a long post, select the whole thing and hit ctrl-C before you post. That way, if you get kicked off, you can just paste it (ctrl-V) into the window and try again."
SR Online Blogmeiser