Setup: RT-AC5300, two Internet connections, ADSL (Primary, WAN port) and 4G (Secondary, LAN port 1). I'm getting IPv6 via ADSL only. Firmware 386.2_2.
If I disable Dual WAN, IPv6 works in both Native and Static modes, "ping6 www.cisco.com" works from the LAN hosts, and they are accessible from...