On Clean install, 3.5.1 with default template, a strange thing occurs when editing Gallery shortcode IF there are more then ONE Gallery in a singhle post.
After edit/ cancel (or save) a shortcode on fresh pageload, and then edit another shortcode on the same post, the new media manager show a cluttered version of both shortcodes/ missing images in the Media manager. Each gallery has more than 12 images.
I find no script errors in debug.
I tried all kinds of edit order, page refresh order, new blank pages with new galleries, new uploaded images, shift between visual editors, in new order, and so on.
When deactivating Media Library Assistant everything works fine. On all installs, all variants in my tests.
I also tried on older installs, live, with diffrent plugins activated and the same issue occurs. MLBA somehow mix things up.
I never seen this before, couse I never used more then one shortcode/ Gallery on a post OR actually tried to edit more than ONE gallery shortcode at the same time.