Hi Andy, could you provide a link to your website?
As far as I understand, your front page displays recent ‘Posts’ by default. But suddenly, perhaps after an update, the front page is displaying recent ‘Pages’ instead. Could it be that this is your first theme update? I wonder if your theme was modified to display ‘Posts’ but these modifications weren’t included in a child theme, so when the theme updated the changes were lost.
Anyways, this is all wild speculation. If you could provide a link to the page in question I would be happy to take a look for you.
Regards,
Chris