Client LAN IP in some but not all NextDNS profile logs

Hi

I have an odd NextDNS issue. I've Googled this a lot and not come up with anything useful, so am starting this thread. 

Network setup

My router is a Ubiquiti Unifi Express (UX), running NextDNS CLI, using profile A. Some network devices don't have NextDNS profiles, and as you'd expect, these show up in the router's logs, some with correct device names, and others with Device # a1b2c3, etc. 

My main client device is a Mac running NextDNS CLI, using profile B. iCloud Private Relay is not enabled on the Mac.

Both profiles are on the same paid NextDNS account.

I have a public IPv4 address (no CG-NAT), and both profiles are using the linked public WAN IPv4 address with a DDNS service updating it every minute.

(My ISP is native IPv6 and I have that enabled. The same issue detailed below happens if IPv6 is disabled, so that's not the problem.) 

Issue

In the router's logs, profile A, I'm seeing

1. client device names
2. client device types
3. client device LAN IPs
4. client device WAN IP.

And that's great. The LAN IP is very useful for tracking down those devices that don't present names correctly e.g. Device #a1b2c3, etc.

In the Mac's logs, profile B, I'm seeing

1. client device name
2. client device type
3. NO LAN IP
4. client device WAN IP. 

Per screenshot attached, when the Mac queries the router directly e.g. for apple.dns.nextdns.io, steering.nextdns.io, etc, the LAN IP of the Mac does show in the router's profile's logs!

So, why is the LAN IP not showing up in the Mac's profile's logs (see other screenshot attached)?! 

What I've done to try to resolve it

• Created new NextDNS profiles and switched the Mac over to them, but no change
• Uninstalled CLI, installed Apple profile, but no change
• Uninstalled Apple profile, installed NextDNS app (from the App Store), but no change.

Further testing done

• On the Mac, I switched the CLI, Apple profile and NextDNS app to use the router's profile ID and it shows up in the logs - with the LAN IP!
• Client devices without NextDNS CLI/profiles/apps show up correctly in the logs showing the LAN IP
• If I apply a conditional configuration to the NextDNS CLI on the router and move some of those unconfigured clients to another profile (using their MAC addresses), then they show up correctly in the logs showing the LAN IP
• It seems this issue is only occurring with clients that have the NextDNS CLI installed locally, an Apple profile, the NextDNS app, or for Windows clients, the NextDNS app or YogaDNS app, and are not using the router's profile ID.

I've been looking at this for the past few days and can't figure out what's going on. Please help!