For the first time today this happened multiple times on the same page. Working on a WW article so there's a lot of jumping around in a template, highlighting and deleting, etc - in both cases it put text back in after I had erased it. Fixed with a control+z. Happened twice so far. I'm definitely outside the window where you would expect the page to still be loading - it's been around 15 mins since I started working on it and the second one JUST occurred.

EDIT: I realized I am using the "preview post" button periodically so it might still be ~1 reload per 'post', sorry this is not that helpful xD