Expected behavior No error

Actual behavior Uncaught (in promise) TypeError: Cannot read properties of null (reading 'disconnect')

Resources (screenshots, code snippets etc.)

MDBAlert.vue : bug

 onMounted() {
        ...
      if (props.stacking && !props.static) {
        setupStacking();
      } 
        ...
    }
    const setupStacking = () => {
        ...
        observerStacking();
    };

 onUnmounted(() => {
  _clearTimeout();
  observer.value.disconnect();       // <--- BUG:  observer is not initialized (null)
                    // when 'static' attribute is set.
});