Date parameter in md file

How does the date parameter in a md file work in relation to whether the page is rendered when Hugo runs? I have a page where I use the date parameter to show when the page was last updated but I find that if I set the date parameter to say “2018-04-01T12:50:00Z” and then run the hugo command at 12:50 I sometimes see that the page is not rendered into the public folder. If I set the date to sometime in the past then it will work but I would like to understand the logic behind how hugo uses the date parameter



For last modification, use lastmod