Hello Piotr, yes the same problem. I saw the typeDefinition of the component and I found that MDBmodal has 3 fields required, is a issue?

do you have a problem with this exmaple too?

 toggle = nr => () => {
    const modalNumber = `modal${nr}`;
    this.setState({
      [modalNumber]: !this.state[modalNumber]
    });
  };

          <MDBBtn color='primary' onClick={this.toggle(2)}>
            Medium modal
          </MDBBtn>
          <MDBModal isOpen={modal2} toggle={this.toggle(2)}>
            <MDBModalHeader toggle={this.toggle(2)}>Modal title</MDBModalHeader>
            <MDBModalBody>
              Lorem ipsum dolor sit amet, consectetur adipisicing elit, sed do eiusmod tempor incididunt ut labore et
              dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex
              ea commodo consequat.
            </MDBModalBody>
            <MDBModalFooter>
              <MDBBtn color='secondary' onClick={this.toggle(2)}>
                Close
              </MDBBtn>
              <MDBBtn color='primary'>Save changes</MDBBtn>
            </MDBModalFooter>
          </MDBModal>