When media files are sent to the trash (media trash feature needs to be enabled), they're still included in the total of the folder file count badges. It would be great if these were not included in the total count. If the media library was filtered only on Trash, then only the trashed files would be included in the folder file count badges.
So if a folder had 15 files in it and all of them were trashed, the attached screenshots illustrate the current behavior.
The desired behavior is 0 files would be indicated by the folder file count badge when filtering on All Media and 15 would be indicated if filtering the media library to show the Trash files.