[Vuejs]-VueJS 3.x composition API: why is v-model property conveyed to component empty?

Sounds like you can’t be sure if the input variable is a ref. You can use unref() to optionally unpack it. Throwing in a check never hurts either:

const unpackedModal = unref(activeModal)
if (unpackedModal) {
  unpackedModal.ref = activeModalRef.value;
}

I think ref couldn’t found in mounted..
You should do this.

    onMounted(() => {
      activeModal.value = activeModalRef.value;
    });