Is this different than some of us writing them (usually taking too long) and then losing them? I've gotten into the habit of copying my text before I submit the entry. Sometimes it posts, other times I have to start a new entry and paste the text into it and hit submit. It always seems to post at that point.
You can just select all the text in your entry and do a Ctrl-C copy right before you click to submit. If it disappears, just start a new entry, paste in, and try again. I haven't lost an entry in a long time using this method. (Except when I accidentally click the "back" button or something!)