Bug Report: WSL2 Network Behavior Diverges from Windows During Mixed Interface Conditions

### Windows Version

Microsoft Windows [Version 10.0.26200.6901]

### WSL Version

WSL version: 2.6.1.0 Kernel version: 6.6.87.2-1 WSLg version: 1.0.66 MSRDC version: 1.2.6353 Direct3D version: 1.611.1-81528511 DXCore version: 10.0.26100.1-240331-1435.ge-release Windows version: 10.0.26200.6901

### Are you using WSL 1 or WSL 2?

- [x] WSL 2
- [ ] WSL 1

### Kernel Version

6.6.87.2-1

### Distro Version

Ubuntu 24.04

### Other Software

_No response_

### Repro Steps

### Steps to Reproduce

1. Connect both Ethernet and Wi-Fi to your Windows machine.
2. Ensure Ethernet is active but does **not** have external internet (e.g., ISP outage).
3. Use PowerShell to `ping www.google.com` — it succeeds via Wi-Fi (e.g mobile phone personal hotspot).
4. Open WSL2 terminal and run `ping www.google.com` — it fails with 100% packet loss.
5. Run `docker pull ollama/ollama` inside WSL2 — it succeeds, albeit slowly.
6. Disconnect the Ethernet cable. You now have just your mobile phone personal hotspot connected to your computer.
7. Retry `ping www.google.com` in WSL2 — it now succeeds.

```bash
(base) sono99@somedesktopcomputer:~()$ ping www.google.com
PING www.google.com (142.250.178.196) 56(84) bytes of data.
^C
--- www.google.com ping statistics ---
11 packets transmitted, 0 received, 100% packet loss, time 10223ms

(base) sono99@somedesktopcomputer:~()$ ping www.google.com
PING www.google.com (142.250.178.196) 56(84) bytes of data.
64 bytes from pnzrha-aj-in-f4.1e100.net (142.250.178.196): icmp_seq=1 ttl=117 time=102 ms
64 bytes from pnzrha-aj-in-f4.1e100.net (142.250.178.196): icmp_seq=2 ttl=117 time=56.8 ms
64 bytes from pnzrha-aj-in-f4.1e100.net (142.250.178.196): icmp_seq=3 ttl=117 time=12.3 ms
64 bytes from pnzrha-aj-in-f4.1e100.net (142.250.178.196): icmp_seq=4 ttl=117 time=15.1 ms
^C
--- www.google.com ping statistics ---
4 packets transmitted, 4 received, 0% packet loss, time 3005ms
rtt min/avg/max/mdev = 12.309/46.522/101.790/36.455 ms
(base) sono99@somedesktopcomputer:~()$ lsb_release -r
No LSB modules are available.
Release: 24.04
(base) sono99@somedesktopcomputer:~()$
```
The difference between failing to ping and succeeding is on unplugging the ethernet cable.

###WSL2 config
- **WSL2 Configuration**:
```ini
[wsl2]
memory=80GB
processors=0
networkingMode=mirrored
```

### Expected Behavior

WSL2 demonstrates inconsistent and unreliable network behavior when both Ethernet and Wi-Fi interfaces are connected, but
only one—typically the slower Wi-Fi—provides actual internet access. While Windows correctly prioritizes the functional Wi-Fi connection for external traffic, WSL2 terminals often fail to establish outbound connectivity under these conditions. Notably, Docker operations such as `docker pull` may still succeed, likely due to integration with the Windows host network stack. However, to restore full network functionality within WSL2, physically disconnecting the non-functional Ethernet cable becomes a necessary workaround.

### Expected Behavior

WSL2 should mirror Windows' routing behavior and use the active interface with internet access (Wi-Fi) even when Ethernet is present but non-functional.

### Actual Behavior

### Actual Behavior

WSL2 fails to reach external hosts via `ping` or other terminal-based network tools when Ethernet is present—even if Ethernet lacks internet access and Wi-Fi is fully functional.

### Diagnostic Logs

You can see in the Cline issue:
[https://github.com/cline/cline/issues/7109](https://github.com/cline/cline/issues/7109)

The `docker pull` command worked perfectly for updating a Docker image.
However, there were clear issues with the `ping` command when executed from within WSL2.
In contrast, the `ping` command worked reliably 100% of the time from Windows PowerShell.

Running `wsl --shutdown` or `wsl --restart` did not resolve the issue.
The only effective solution was physically disconnecting the Ethernet cable from the network interface that lacked external internet connectivity.

Reproduce the setup with WSL 2 mirrored networking, Ubuntu 24.04, and both Ethernet and Wi-Fi connected while only Wi-Fi has internet access. Compare PowerShell and WSL2 ping behavior, and check whether Docker pull still succeeds; done means WSL2 uses the reachable interface without requiring the Ethernet cable to be disconnected.

Written by the indexing model from the issue text.