Hi !
I came from France and I want to configure an ER605.
The configuration:
WAN: Livebox Pro
Port4: LAN1, VLAN10, 192.168.10.0/24

Port5: LAN2, VLAN20, 192.168.20.0/24

LANs are isolated.
Ports are configured with the good PVIDs.

In Firewall -> Access Control, The two subnets are Blocked in the two ways.
Ping don't work, so it's is OK.
But.... 

The SMB protocol always passes between the two subnets when in principle, everything should be blocked. Where does the problem come from? What other protocols could pass through the gateway when the networks are supposed to be isolated?

The NetBIOS broadcast could be a problem with this router ?

Big thanks for Your help