I’ve just noticed this behaviour, and I want a fix as well. My “Other Videos” library only includes 16:9 vids, and the thumbnails for individual vids are all in landscape, but the collection I’ve just created (again, only 16:9 vids) insists that the vids within it must all have portrait thumbnails. Even worse, the auto-generated thumbnail for the collection, which is in portrait, is cropped to landscape in the main library view.
I think this looks terrible and should absolutely be an option, not forced on us.
