It is highly likely that this refers to a you encountered.
An insider threat or a compromised process could use the discovery mechanism to locate a writable FTP folder. The attacker uses cdn1discovery ftp to answer: “Where can I dump these 10 GB of stolen documents?” The discovery service returns an FTP upload URL. cdn1discovery ftp
Partners who provide content to Discovery are often given specific FTP credentials and hostnames (like ://cdn1discovery.com or similar variants) to deliver their shows, trailers, or advertisements. Best Practices for FTP Transfers to CDNs It is highly likely that this refers to a you encountered