The auto created buffer link to post links to wp admin login page

Need to use the {url} tag in the status:
https://www.wpzinc.com/documentation/wordpress-buffer-pro/status-text-tags/#available-tags

If your assertion is that you are already doing this, need to provide screenshots of settings for replication of the issue.

Yes I am using the url tag, see screenshot: https://ibb.co/DfTJhxs

It’s likely that a third party Plugin is interfering with this, noting that the {url} tag calls the WordPress standard get_permalink() function, which always returns the link to the frontend Post.

Feel free to enable Troubleshooting Mode per Docs to establish which third party Plugin causes this issue, and work with them to resolve accordingly:
https://www.wpzinc.com/documentation/installation-licensing-updates/troubleshooting/#run-health-check–amp–troubleshooting

Thank you!