Can't share to Linkedin

Hi,
My client has come to me with a random problem. When she tries to share a post to Linkedin it redirects to the login page.
Please see private link for the page.

The weird thing is when I use the Linkedin post inspector it works. https://www.linkedin.com/post-inspector/
Then when I try and share the post from within the site, it miraculously works.

Sometimes the post inspector says:

Ingestion feedback
Warning Add an og:description tag to the page to have control over the content’s description on LinkedIn.
Warning Add an og:image tag to the page to have control over the content’s image on LinkedIn.
URL information

Last scraped a few seconds ago
Fetched URL https://www.xxx/case-study/
URL redirect trail

1 307 Redirect https://xxx/case-study/
2 302 Redirect https://xxx/wp-admin/
3 200 Success https://xxx/wp-login.php?redirect_to=https://xxx/wp-admin/&reauth=1