My experience is that Bridge II is finickier then advertised. Much to my consternation, You can’t communicated with Bridge II via it’s IP address. It used to be a great way to re-set the UPnP server for the times Bridge I wouldn’t show up in JRiver.
The only way I was able to successfully set a static IP for Bridge II was through the set-up screen of the DS. You have to select the Bridge and work your way through the menus to then de-select DHCP. Then add the IP address you want to use, sub-net, DNS…
I also had the Fing issue you’re discussing. It’s showing the legacy address (probably grayed out). I would delete all the previous scans, then scan the network again using Fing. Bridge I should be gone.