Warning: Failed propType: Calling PropTypes validators directly is not supported

Question

I've been trying to add grid to my react project but when I load the page it gives me an error:

Warning: Failed propType: Calling PropTypes validators directly is not supported by the `prop-types` package. Use `PropTypes.checkPropTypes()` to call them. Read more at https://github.com/facebook/prop-types/blob/master/README.md#difference-from-reactproptypes-dont-call-validator-functions Check the render method of `GridTest`.

Tried using antd and react-flexbox-grid, but both libraries produce the same error.

Code:

    import React, { Component } from 'react';
    import {Grid, Row, Col} from 'react-flexbox-grid';

    export default class GridTest extends Component {
        render() {
          return (
            <Grid>
              <Row>
                <Col xs={6} md={3}>Hello, world!</Col>
              </Row>
            </Grid>
          );
        }
    }

Any suggestions on how to fix this? I think problem might be caused by external lib not bundling prop-types or something?..