I recently updated to WP 5.3.1

And now, when I create a new post, it mixes up with previous posts.

Also, when I reload the post list index in the WP admin area, it will not display the last published post until I hit reload a few times.

Something that bothers me a lot is, that when I publish one post, and then create a new one, it will update the last post instead of creating a new one.

This seems to be a cache-related issue, but I am not sure and maybe it is a bug in the new version.

I use the WP Super Cache plugin, but as far as I know, it does not affect the admin area, only the public side of the site.

I asked my hosting provider if they are doing some extra cache, but they are not.

I also recently added Header set Cache-Control "max-age=31536000, public" to my .htaccess file (but I removed that). Do you think that might be causing the problem?

What else might be happening?