This question has been answered by todd.b. See the first response.
"Hag sameach" to the both of you (Passover today).
If the templates are identical, are the resource IDs also the same? That's what I meant by "the wrong &parents property".
It might be something like this: http://bobsguides.com/blog.html/2013/05/22/dude,-wheres-my-article-disappearing-articles/
[2014-04-16 11:42:19] (ERROR @ /connectors/resource/index.php) Could not load class: ArticlesContainer from mysql.articlescontainer.
[2014-04-16 11:45:43] (ERROR @ /assets/components/articles/connector.php) Encountered empty IN condition with key contentid
[2014-04-16 11:45:43] (ERROR @ /assets/components/articles/connector.php) Error 42000 executing statement:
Array
(
[0] => 42000
[1] => 1064
[2] => You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near ') )' at line 1
)