Something has changed on me recently. Instapaper epubs of articles from e.g. New York Times, no longer display the body text on either my Kobo Touch or in Adobe Digital Editions


If I load the epub in Calibre I can read the text fine. On the Kobo or ADE I only get the heading and no text.
I tried an experiment of loading the epub in Calibre and doing a epub->epub convert and resaving it. After that the epub worked fine in ADE and on the Kobo.
What is going on?
Instapaper, ADE & Kobo were all working fine for me a month ago. What's changed?