Today I wrote and edited a new post. It previewed correctly. When I submitted it, the new posting was blank. A poster on the Missing Whitney Hiker: thread also noted that the entire text did not post.
The issue is the use of "curly" quotes and apostrophes. In my case, I copied from a source which used curly style.
I used Windows for the post, Macintosh users may have a different experience.
This is apparently due to changes in the site's underlying language.
Verum audaces non gerunt indusia alba. - Ipsi dixit MCMLXXII