This 100% happens.
https://www.washingtonpost.com/sf/style/2014/11/26/how-miria...
When this^ woman was murdered, I attempted to post on Facebook: "I bet this woman was not a terrorist." to which I was told the attempt failed.
After troubleshooting, such as trying again or posting something else, I felt very deceived.
I mean.. that's an anecdote which could have a myriad of technical explanations. I wouldn't immediately jump to the assumption that facebook is blocking select users from sharing links from a respected newspaper because they don't like the content of the article for some reason (why would they even block this article in specific?)
* washingtonpost is behind a GDPR paywall (for me at least), it took a few attempts even for the link preview to load when I tried posting that
* 99.9999% uptime of web APIs is not 100%, fb servers really could have been having trouble reaching washingtonpost
* I was able to share that post fine (once the link preview finally loaded properly), so WFM..?