I use a WD mycloud to hold all my movies. It has worked fine in a long time but suddenly I have double up on covers when I look through my movies with Infuse on my Apple TV 4
I have checked the WD mycloud and there are only one movie of everyone- not 2 or 3 of every single one.
Are you connecting via UPnP/DLNA by chance? In some cases when streaming via either of these, Infuse may display duplicates while your NAS is updating/scanning.
Connecting via SMB, NFS, FTP/SFTP, or WebDAV can help avoid this.
A quick test would be to try and browse for a new share via Infuse > Settings > Shares. If multiple connection types are available you’ll see them listed in parenthesis.