Not on the Discourse side, I believe.
The next step would be testing this assumption.
Make sure you’ve followed the Cloudflare Guide.
Disabling Cloudflare temporarily may help, but Twitter/LinkedIn might cache their results and this may not have immediate effect.
Access logs might have more information.
Posting on Cloudflare’s Community about this may help.
I note that https://community.cloudflare.com/ does appear properly on Twitter/LinkedIn, for what it’s worth, so evidently they’ve made this work.