FTP Server OS: Windows
FTP Server Type: Windows Server IIS
Client Computer OS: Windows
FluentFTP Version: 50.0.1
Framework: .NET 4.8.1

I have an app that generates around 1000 XML files (in subfolders). It then uploads a mirror to the FTP server. So, most of the time it's overwriting files with newer versions of themselves.
Occasionally, if there are files to remove, it will remove ALL files, not just the extras. The FtpResults report success.

No logs at this stage...