node_access table truncated when used with modules employing hook_node_grants()

When performing an import, the node_access table gets truncated when the site employs any module that implements hook_node_grants(). This is due to the following line in cloudwords_import_batch_finished():

//negate unpublished node access granted to scraper
node_access_rebuild(true);

The problem is that setting the $batch_mode flag to TRUE on node_access_rebuild() tells it to rebuild the node_access table using a batch process if there are any modules that implement hook_node_grants(). This batch process will never kick off however as node_access_rebuild() is being called in the Cloudwords import batch success callback, which is not a viable context to kick off another batch process. So node_access_rebuild() truncates node_access but is never able to rebuild it which obviously has really bad consequences.

The deeper question here is if node_access_rebuild() is even necessary. From what I can tell, the scraper is given view access to the node using hook_node_access() which does not modify the node_access table. Is there someplace that I'm missing where the node_access table is modified and therefore requires a rebuild?