I recently updated an old post, to add a link to a newly published post - and experienced panic. Adding a link to an old post, Deleted / Locked Blogs Have Several Causes , I discovered an oddity which caused extreme heartburn for several hours. Maybe you have experienced this, also. Editing my post, and adding a simple single sentence, with embedded link, at the end of the post, I refreshed the display (always test your changes - no matter how minor!), and watched as the paragraphing scrambled itself.
What Blogger won't tell you