Custom post option not working

I set up a custom option in Write Options – Post, logged in as a test author using incognito but the meta box was still visible. Double checked users role. Cleared the site cache totally, cleared browser cache. Tested it with another field. Also didn’t work.

Here is a screenshot showing the div ID using Chrome dev inspector.
Here is a screenshot showing the entry in Adminimize Post Options.

I checked other support questions relating to the same issue but I do seem to be doing this correctly.