I was unable to access a number of nodes in my site with a "The website encountered an unexpected error".
This showed up:
Notice: Trying to get property of non-object in ds_field_formatter_view() (line 1238 of /srv/www/site/public_html/sites/all/modules/ds/ds.module).
EntityMalformedException: Missing bundle property on entity of type taxonomy_term. in entity_extract_ids() (line 7633 of /srv/www/site/public_html/includes/common.inc)
As far as I was able to track it this seemed to happen only when I specifically enable the option Format = "Separated" for a "Term Reference" field type with a "taxonomy autotag field" widget associated (the other Format options work fine!),
Contrary to other similar items which work correctly the troublesome one has the single specificity of being associated with OpenCalais.