Failed to get input node 6 for group node child 175:1 with slot 0(flux-kontext-dev-grouped)

### Custom Node Testing

- [x] I have tried disabling custom nodes and the issue persists (see [how to disable custom nodes](https://docs.comfy.org/troubleshooting/custom-node-issues#step-1%3A-test-with-all-custom-nodes-disabled) if you need help)

### Expected Behavior

When I attempted to test using the preset example flux-kontext-dev-grouped from comfyui, the operation failed. The system displayed an error message: "Failed to get input node 6 for group node child 175:1 with slot 0"

I'm a beginner and I'm not very clear about what this error means. Could someone please explain it to me?

### Actual Behavior

### Steps to Reproduce

Select the official preset template "flux-kontext-dev-grouped" and click the "Run" button.

### Debug Logs

```powershell
Failed to get input node 6 for group node child 175:1 with slot 0
```

### Other

_No response_