I am new to sharepoint and just started learning sharepoint.I am facing one issue

Suppose

1. one admin user login to sharepoint site changed one page's end date to specific date and checked in the page
2. then user from owner group published the same page .he can publish the page without error

Now
1. admin user again login and set same page's end date to never .
2.then user from owner group tries to publish the page .
he gets access denied error.