By any chance, are the 2 scanners that disconnect and reconnect running Windows 2008? We ran into something similar with our scanners running McAfee AV for NetApp on Windows 2008 servers. It came to light after we upgraded our DOT to 7.3.6 and enabled SMB 2. It seems that SMB 2 uses a certificate system that expires and forces the scanner to disconnect and reconnect. McAfee suggested we disable SMB 2 on the scanner servers.