Change the validation so that the messages are now presented to the user (previously they were only logged). This showed up a number of errors in the import. Once these errors were fixed, the test designs worked properly and the valid flag was set, allowing preview to be run straight away (
LDEV-862).
The problems were not spotted earlier as the data in the database still came out correctly when the learning design packet was sent to authoring - it was only the entries in various sets when the validation was run that was the problem.