I have a page set as my posts page (i.e. posts are not the home page).
I have a page header assigned in global locations to the posts page.
That page header uses {{post_title}}
When I load the posts page, it loads the correct page header, but it does not pull the title of the posts page. The title is completely blank. When I use that page header with any other page, it works fine. This seems to be a bug.
I would suggest maybe changing this in a future version because it seems to make sense to use the page title in this case as well. Thank you for the answer!