False Positive when using errGroup

[QianKuang8]

Nilaway fail to get the correct answer when using errgroup(case1). But it works fine in normal case(case2).

package main

import (
	"context"
	"fmt"
	"golang.org/x/sync/errgroup"
)

func getData(s string) (*string, error) {
	if s == "" {
		return nil, fmt.Errorf("empty data")
	}
	return &s, nil
}

// Not OK
func case1() {
	g, _ := errgroup.WithContext(context.Background())
	var s *string
	g.Go(func() error {
		var err error
		s, err = getData("hello")
		if err != nil {
			return err
		}
		return nil
	})
	if err := g.Wait(); err != nil {
		return
	}
	fmt.Println(*s)
}

// OK
func case2() {
	var s *string
	var err error
	s, err = getData("hello")
	if err != nil {
		return
	}
	fmt.Println(*s)
}

func main() {
	case1()
	case2()
}

// error: Potential nil panic detected. Observed nil flow from source to dereference point:
//	- hello_world/main.go:30:15: unassigned variable `s` dereferenced