leastDestructiveRef of CAlertDialog seems not working

[odiak]

Describe the bug
I specified CAlertDialog's leastDestructiveRef with ref of second button, but the first button was initially focused.

<CAlertDialog
    :is-open="isOpen"
    :least-destructive-ref="$refs.cancelRef"
    :on-close="closeDialog">
  <CAlertDialogOverlay />
  <CAlertDialogContent>
    <CAlertDialogHeader>...</CAlertDialogHeader>
    <CAlertDialogBody>...</CAlertDialogHeaderBody>
    <CAlertDialogFooter>
      <CButton>Do it</CButton>
      <CButton ref="cancelRef">Cancel</CButton>
    </CAlertDialogHeaderFooter>
  </CAlertDialogContent>
</CAlertDialog>

Expected behavior
Second button is focused initially.