Adguard DNS Protection is not working well with router advertised dns servers

As title says, my router pushes their relay dns server address to client.
From what i experience on using router asus ac86u, when IPv6 connectivity enabled on both macOS network adapter and router. We'll have both IPv4 and IPv6 Wan Address assigned to client (macOS), including at least two DNS servers (one is IPv4 and another one is IPv6, both are relay dns server, which is router itself ip address).
In my case, first dns address is router IPv4 address (private ip) and second dns address is IPv6 address (**wan** ip not link-local ip)
I try to override dns setting to get rid of IPv6 one, and it works well
It won't work well when the IPv6 one is used (either using it alone or using it with IPv4 one)
If i set public ipv6 public dns address as dns instead of using the router ipv6 one, it works again

### Steps to reproduce

1. A little bit hard to reproduce this issue as i can only reproduce it with my router (asus ac86u)
2. Set up IPv6 enabled on both side (macOS and router)
3. Leave any DHCP and DNS setting with default value on router
4. Join the router wireless / ethernet network to get DNS settings pushed onto our system (macOS Monterey 13.3.1 with Adguard for Mac 2.8)
5. Set up Adguard DNS Protection
6. (4.1) Enable DNS Protection
7. (4.2) Choose Adguard DNS instead of System default
8. Go to adguard check website `https://adguard.com/en/test.html`

### Expected behavior
See Adguard DNS is detected as the page shows

### Actual behavior
Adguard DNS is not detected as the page shows

Screenshot:


### Customer ID
595342

### Your environment
* macOS Monterey 13.3.1
* Adguard for Mac 2.8.0.1133 release
* Router with IPv6 connectivity enabled