I am having an issue where I cannot save page type settings in 5.6.1. I have a homepage page type and a full page type. I have now created a file called left_column.php and uploaded it into my theme folder. I then inspected the theme to add the page type. The page type shows up correctly, but I cannot edit any of the settings in the dashboard. I just want to change the icon and add the Meta Title property.

Any ideas on how to fix this?