We have an RB532 set up in a small company as their primary router. We are using all three interfaces, ether1 to the WAN, ether2 to the LAN, and ether3 to a remote building (LAN2).
A computer in the remote building needed access to their Windows share resources (printers and file shares). So we bridged ether2 (LAN) top ether3 (LAN2).
No matter what we tried with WINS, HOSTS, LMHOSTS, etc., nothing seemed to work. We just could not get the one computer in the remote building to access Windows shares.
So we connected the remote LAN2 into the LAN switch (connected to ether2/LAN), and everything works perfectly.
So why did the MT bridge not work? Looking at the firewall rules, there doesn't seem to be any rules that were "firing" to block NBT traffic.