Ah you actually have an interface group for the WANs with the rule on it?
Yes, if you do that reply-to tags cannot works because the rule applies to multiple interfaces. It cannot know which interface (gateway) to reply to.
For reply-to tagging to work incoming traffic must be passed on the interface itself. It's the same reason that OpenVPN traffic must be passed on an assigned interface for repy-to to work. The group openvpn interface will not tags it.
@Sergei_Shablovsky said in [SOLVED] NTP not answering on 2-nd uplink WAN:
And in System / Routing / Gateways this BALANCED group set as “Default Gateway IPv4”
That's still invalid. The system default gateway should only be a specific gateway or a failover group. You cannot load-balance traffic like that.
Steve