Error in SharePoint Online 2013 When Importing Site Template

What happens if you upgrade one site collection from SharePoint Online 2010 to SharePoint Online 2013, then go to the root site, export it as a template with content, then import the template in a 2013 site collection and try to create a subsite based on that template?
You get this useful error:

An error occurred while processing the request on the server. The status code returned from the server was: 0

 Very clean error otherwise:

EDIT: it turns out this is caused by working as a delegated admin. Still a bug, but you can work around this by creating a user in the tenant and giving it site collection administrator rights. Of course, if you have an available license for that.