Recently I ran into an issue where I had to generate content within a Drupal 7
cron run using
node_view(). Normally there wouldn't be much of an issue here
except that I was also trying to do some custom work within
the main theme for the site.
After much frustration, I learned that during cron, the administration theme
is used. After some thought, that makes sense and normally would not cause any
issues but in my case it caused nothing but pain.