I checked a few of the posts on your Facebook Page, a received a 404 error on this page:
https://archdesignnq.com.au/2013/04/24/yardley-court-bowen-2/
The problem is not linked to Jetpack though: that post was published with this URL at one point; it got indexed by Google, so it was working when you originally published it:
https://goo.gl/sJhoM
However, the post doesn’t appear on your site anymore: did you rename the post and change its URL, or did you delete it?
I also experienced issues with this post:
https://archdesignnq.com.au/2013/05/17/architecture-for-adaptive-retrofitting-and-reuse/
This post also existed at some point, and was indexed by Google, but it now redirects to a new post:
https://archdesignnq.com.au/2013/05/17/extra-room-for-a-family/
Did you change the post URL after publishing it, or do you use any redirection plugin on your site?
Once your posts are shared publicly, it’s usually recommended not to change their URL, to avoid such issues.
They also don’t appear in LinkedIn.
Could you try to reset your LinkedIn connection, as explained here?
https://jetpack.me/support/publicize/#reconnecting-linkedin
Let me know if it helps.