If a page is shared before making edits to the page, Facebook will cache that content and it does not get updated as you make updates to your page. One solution would be to not share your page on Facebook until the page setup is complete. If you have already shared the page prior to making edits to it:
1. Visit Facebook’s developer debugger (https://developers.facebook.com/tools/debug).
2. Enter the URL of the page in question and hit the “debug” button.
3. Go back to your page and share the URL. You should now see the up to date content.