Lately I have been baffled by the appearance of empty Twitter Cards on pages where there is no twitter:card meta tag set. This happens on posts without an image. Some OpenGraph tags are used, but not og:image. For posts with an image, both the relevant Twitter and OpenGraph tags are set.
However, the Twitter Card Validator reports the card tag when there is none.
Now why would Twitter think there is a card when there is none? What am I missing?
http://emilykocken.nl/de-man-met-het-loopje/ INFO: Page fetched successfully INFO: 18 metatags were found INFO: twitter:card = summary tag found INFO: Card loaded successfully