React doesn't render my Component, only if I restart my project

render(){
    const dummyText = 'Lorem Ipsum is simply dummy text of the printing and typesetting industry. Lorem Ipsum has been the industry\'s standard dummy text ever since the 1500s, when an unknown printer took a galley of type and scrambled it to make a type specimen book.';
    return(

      <Card className={styles.card} key={this.props.id}>
        <CardTitle
          title={this.state.project.project_name}
          subtitle={this.state.project.category}
          />
        <CardText>{dummyText}</CardText>

            {this.state.project.skills.map((skill) => {
              console.log('Skill is: ',skill);
              return (
                <CardActions key={skill.id}>
                  <Chip>{skill.skill_name}</Chip>
                </CardActions>
              );
            })}

      </Card>
    );
}

// *-----------------------*
// |  MAIN-APP COMPONENT   |
// *-----------------------*

import React, { Component } from "react";
import { Col, Well, Panel } from "react-bootstrap";
import { Route, Switch } from "react-router-dom";

import SideNavComponent from "./SideNavComponent";

const HomeComponent = () => <div>Home</div>;
const GraphComponent = () => <div>Graph</div>;
const DeviceComponent = () => <div>Device</div>;
const TransformationComponent = () => <div>Transformation</div>;

class App extends Component {
  render() {
    return (
      <div>
        <div className="header" />
        <div className="body">
          <Col md={3}>
            <Well>
              <SideNavComponent />
            </Well>
          </Col>
          <Col md={9}>
            <Panel>
              <Switch>
                <Route path="/device" component={DeviceComponent} />
                <Route path="/transform" component={TransformationComponent} />
                <Route path="/graph" component={GraphComponent} />
                <Route exact path="/" component={HomeComponent} />
              </Switch>
            </Panel>
          </Col>
        </div>
        <div className="footer" />
      </div>
    );
  }
}

export default App;

// *-----------------------*
// | SIDENAV-COMPONENT     |
// *-----------------------*

import React, { Component } from "react";
import { Nav, NavItem } from "react-bootstrap";
import { Link } from "react-router-dom";

class SideNavComponent extends Component {
  render() {
    return (
      <div style={{ flexDirection: "column" }}>
        <Link to="/">Home</Link>
        <Link to="/graph">Graphs</Link>
      </div>
    );
  }
}

export default SideNavComponent;

// *-----------------------*
// | MAIN.JS (ENTRY POINT) |
// *-----------------------*

import React from 'react'
import { render } from 'react-dom'
import App from './components/App';
import { BrowserRouter } from 'react-router-dom';

render((
  <BrowserRouter>
    <App />
  </BrowserRouter>
), document.getElementById('root'));

import { Provider, connect } from 'react-redux';

class RootContainer extends Component {
  render() {
    const {locale} = this.props
    return (
        <ThemeProvider theme={colors}>
                  <FormattedWrapper locale={locale} messages={messages}>
            <Root>
              <StatusBar barStyle='light-content' backgroundColor='transparent' translucent />
              { Platform.OS === 'android' && Platform.Version >= 20 ? <StatusBarAndroid /> : null }
            <Navigator />
          </Root>
                    </FormattedWrapper>
        </ThemeProvider>
    );
  }
}

const mapState = state = ({
   locale: state.language.language
})

ConnectedRootContainer =  connect(mapState, null)(RootContainer);

class App extends Component {
  render() {
    return (
      <Provider store={store}>
        <ConnectedRootContainer/>
      </Provider>
    );
  }
}

export default App;

import { add } from './math';

console.log(add(16, 26));

import("./math").then(math => {
  console.log(math.add(16, 26));
});