Updates say they work but no file changes occur

When I try to update (both plugins and themes) it goes through the motions, tells me everything’s great but when I get back to the Updates page nothing has changed. I look at the version numbers in the readme files and, sure enough, nothing has been updated.

The update process is starting. This process may take a while on some hosts, so please be patient.

Enabling Maintenance mode…

Updating Plugin Google Analytics for WordPress (1/1)
Downloading update from http://downloads.wordpress.org/plugin/google-analytics-for-wordpress.4.2.8.zip…
Unpacking the update…
Installing the latest version…
Removing the old version of the plugin…
Plugin updated successfully.
Google Analytics for WordPress updated successfully. Hide Details.

Disabling Maintenance mode…

All updates have been completed.

It looks like it works but nothing changes.

I’m on a shared host and all my directory and file permissions seem fine.