Why isn't the value for a new Boolean field rendered? I added a new Boolean field to a content type. For some nodes, I did set this field.


  


Still, the field value is not shown on the node page.


  


Why?

I realize that, as long no value is set for the new field, it isn't present in the database, but (as seen in the screenshots) on that node, the field is set to true and it should be shown on the node page, shouldn't it?
This is a Durpal 7 Problem.
It lies about that it will fall back to 0/1 if you don't provide your custom true/false values, when it actually does not fall back.
See
https://www.drupal.org/project/drupal/issues/1750950

In short, in the field-settings, you have to set on-/off- values.
If you don't the default renderer will output an empty string and in the edit forms the field's checkbox or radio-buttons will have no label.