Hi there, thanks for the response!
It turns out there was a widget that had a custom function in it. The logic in the widget did something like this:
function some_function($post_id)
{
//make a wordpress DB query using $post_id
}
global $post;
some_function($post->ID);
The problem is that $post, for the page being rendered, was an integer representing the post id, and not the actual $post object as would have been expected! Not sure why that is, but I got rid of the logic and everything worked again.
