New post page, screen options not "sticking"

I have been trying to move modules around on my new post page and something appears to be broken.

I can move the modules but upon coming back to the page, nothing has “stuck”.

I have tried:
-clearing cache and cookies
-disabling certain plugins
-disabling all plugins
-deleting completely newer plugins
-checking files to see if they’ve been changed by any plugins
-checking databases to remove any possible tables left by plugins (there weren’t any)
-overwriting wp-admin and wp-includes folders

While it’s not a major problem, it bothers me that I can’t seem to fix it. Does anyone have any further ideas for a possible fix?

Thanks in advance