Posts won’t link to my Share Message Text

My Share Message Text is not being shared on some of the social media platforms, including Facebook, Google+ and Instagram. Instead it shares a link to the page, and use content from that page in the post.

I need to be able to control my Share Text Message on these platforms, so I can link to various URLs for the different images that are being shared.

It works fine on Twitter and Pinterest.

Thanks for your help!