The site is access restricted, I am not sure how the view is designed in this case.
You have mentioned the view returns 7 results but only 4 are visible in the Map in such case i would recommend checking the Address fields for the missing markers and make sure they have proper address that is recognizable by Google maps.
Also check the browser console for any error.
It would be good if you can share temporary access to the site also let me know the Url where the issue can be seems.
so that I can take a closer look in to the issue.