Corrupted files when uploading via FTP in the /upload directory

Dear, I have more than a thousand files that I need to associate with notes to include in the history of clients. I made the correct association of these files via database. but all files become corrupted when uploading via FTP in the / upload directory.
Has anyone had this? I already have my files are perfect, named properly, however the simple fact of uploading within the directory / upload causes the files to become corrupted.
Is there any configuration within Suitecrm that causes this to occur?
Definitely the problem is not on the server, as I tried on 3 distinct servers and the problem occurs in the 3.
I am attaching an example. See how the file gets … it gets completely strange AFTER uploading the file via FTP.
When I use the upload function inside the notes module the files are normal, however I have more than a thousand files to upload so I need to do it directly through ftp or it will take forever.