Storyline 360, unusual caching issue when publishing
Thought I'd leave this here for future reference, in case anyone else has this issue.
We have just produced 10 different language versions of the same course for a client. On publishing the courses, we noticed that after the first published instance, all subsequent published courses will re-use any of the same assets found in the first published instance (by filename I think). For us this meant a button graphic (for each language) was never updating.
The fix is remove the folders starting with "Publish." in the following location, before hitting 'Publish':
Hope this helps someone in future, as the official documentation only lists the usual temp folders.