Hover using Reference affect both child in react components

class ResponsivePaper extends Component {
  constructor(props) {
  }

  changeBackground(e, currRef) {
    currRef.current.style.background =
      "linear-gradient(0deg, rgba(34,193,195,1) 0%, rgba(0,0,0,1) 100%)";
    currRef.current.style.color = "white";
  }
  resetBackground(e, currRef) {
    currRef.current.style.background = "white";
    currRef.current.style.color = "black";
  }

  render() {
    const { classes } = this.props;

    return (
      <div className={classes.root} id="parent">
        <Grid container spacing={3}>
          <Grid item xs={6} sm={4} lg={3}>
            <Paper
              className={classes.paper}
              elevation={15}
              ref={this.parentRef}
              onMouseOver={e => this.changeBackground(e, this.parentRef)}
              onMouseLeave={e => this.resetBackground(e, this.parentRef)}
            >
            </Paper>
          </Grid>
        </Grid>
        <Grid container spacing={3}>
          <Grid item xs={6} sm={4} lg={3}>
            <Paper
              className={classes.paper}
              elevation={15}
              ref={this.Paper2}
              onMouseOver={e => this.changeBackground(e, this.Paper2)}
              onMouseLeave={e => this.resetBackground(e, this.Paper2)}
            >
            </Paper>
          </Grid>
        </Grid>
      </div>
    );
  }
}