I just purchased this yesterday and was working on getting this set up on my development site. While working with overriding some templates a notification for a new version of Joomla came up. I did the install and noticed the the artist image on the main page (show artists on MC home is set to yes) disappeared. Functionally everyhing was still working. I inspected the page and it appears that an empty url was being returned for the artist image.

I deleted all of the images in the cache/muscol and cache/muscol/artists directories. After reloading the website, the images that were in cache/muscol were successfully recreated, but the cache/muscol/artists directory was still empty.

I set the thumbnails configuration setting to 'STATIC' and resized the artist image I was using. After saving the new artist image, the main page displayed correctly.

Please let me know if this is in fact an issue with the latest Joomla update, or is there something else that I may be missing.

Thanks!