I believe I faced some issue: I needed to upload 195Mb file to my local hosted Mattermost with S3 to host files (from my virtual machine provider, not AWS). The file was reported to be uploaded Ok (after I adjusted the settings on Console to upload such a large uploads, but then we try to download it, it just give 8Mb file.
If try to download it via public link, it gives back all 195Mb, but the archive is corrupted.
I also checked my S3 storage, and there are 39 files - all of them of 5Mb, except for one (the last one), which 1,35Mb (screenshot attached).
I tried to Google the issue, and it says it could be something related to nginx upload settings.