I experienced a bit of really weird behavior on superuser this morning. I created a new ticket, and in that ticket I had made two links. The first link I added after typing some stuff, and I made it by selecting some text in the editor, pressing ctrl+l, pasting my link in there, then hitting ok. It worked fine, and the text in the preview was correct.
When I submitted the ticket, the entire block of text between my first and second link became part of the hyperlink. When I went to edit the post, the actual markup looked to be ok, so I removed the first link from my post. After I saved my edits, there was no history of the previous version to be found!
Edit: Ok, I guess that there is an explanation for that behavior, as Kent points out.
I realize this sounds very crazy and probably hard to reproduce. It would be nice if we had some type of sandbox to experiment around in without having to worry about generating a bunch of junk questions on the site, or does such a thing already exist.
FWIW I'm using chrome on vista.