We are experiencing a strange issue with doctype allowed template settings disappearing. The issue happens sporadically (but regularly) but seems particularly triggered when copying a content node. We can reset the allowed templates and for a while they're ok before disappearing again. The CMS users are starting to get annoyed with me!

The problem manifest itself as content nodes having no available templates (including no default) and the doctype admin page having no template checkboxes selected.

We have a large number of content nodes so unfortunately can't easily delete and recreate the offending doctypes. 

Has anyone seen this issue before or would perhaps know where we should look?

Thanks for any help or advice! Please please help!

Bill