A quick review of the issue:
My initial issue was that the DIR-868L 'appeared' to be confusing the NetBIOS browser announcements and election process on my local network. By confusing I simply mean network shares did not browse correctly and consistently across multiple clients, when the 868L had its status as MASTER. I was not able to easily disable this, but could pull the cable feeding my local network at the back of the 868L.
With it abruptly offline for a few minutes, one of my Dlink DNS-321 NAS boxes would win the MASTER browser status, and all browsing was then apparently 'fine'.
So I looked for a quick/simple way to disable the 868L's participation in NetBIOS 'host announcements' since it was a new device (at that time) on my network, and I just needed it excluded from the process. Longer term I needed a better solution.
My first attempts at 'longer term' involved trying to disable the DIR-868L's participation in this process by using the WebGUI and disabling Media Server features for each service listed ( DLNA, Itunes, USB 3.0 ). Disabling all of these did not prevent the 868L from participating in NetBIOS 'host announcement' transactions on my local network, leaving it 'available' to compete for master at future times.
A quick update from efforts over this past weekend: ( quick read / workaround = remove any USB connected media and reboot 868L )
1. In the Media Server screen of the 868L's WebGUI, the USB 3.0 port has settings of 'Enabled' and 'Disabled'. These merely change the flavor of the USB port from USB 2.0 to USB 3.0 (per the latest documentation) These settings do not control the USB port being a member of the devices shared by the media server. Inside the WebGUI built in "HELP" for the 868L, this USB port is not addressed.
2. If any media is plugged into the USB port on the rear of the 868L, the 868L will start a process for sharing this media, and begin NetBIOS host announcements for that device. The 868L will not stop advertising these even if they are pulled from the USB port. I waited for over an hour to see if this would change. It did not.
3. The 868L will stop the host announcements if, after you remove any USB media from the USB port, you warm boot (or cold boot) the 868L.
4. IF you just remove the USB media and do not reboot the 868L, it will still participate in host announcements, and it will attempt to gain Master Browser if an election is started. Its election process packets indicate it has a OS Level 20, and competes with my 2 Dlink DNS-321's which are also OS Level 20. The winner will be the device with the longest uptime.
5. For the moment the work-around is = no media attached to the USB port.
6. Another workaround is likely just putting the 868L in a different workgroup. Not one I'd prefer but at this point that would suffice.