We've been experiencing a very bizarre and hard to diagnose issue with images that are pushed to S3 not having their database records properly updated to reflect they are propagated. This is leading to random broken images on the site (as it's trying to use the local filesystem path), despite the fact that the file exists on S3.
Basically it seems to have a problem with files with similar names.
For instance, right now I have two files on S3 with the "same" name: Entrance.jpg AND a file called entrance.JPG - they are different images on S3, and downloading them from S3 gives me two different images.
The storage_instance table says entrance.JPG is on S3, but the storage table's serving_container field still refers to the filesystem.
Here's where it gets weird - in the file_managed table, the filename has been re-named entrance_1.JPG. I assume this is because it checked the database for files of the same name. The storage_core_bridge table also refers to this file as entrance_1.JPG.
However, there is no entrance_1.JPG file on S3 - only a entrance.JPG file as it was originally uploaded. I'm thinking this might be a problem with S3 accepting Entrance.jpg and entrance.JPG as distinct files which is confusing the propagator.