Hi Gabe,
Is there a commonality between the three sites? Is there a shared theme, shared plugin, shared mu-plugin, etc? Is there some shared code in their themes or anywhere else?
Can you try deactivating all your plugins to see if the issue persists? Try switching to a default theme (eg. TwentyFifteen) too.
Let me know if you find a plugin or theme which is causing the problem.
I did try disabling all other plugins on my local site. I just did again while also switching between twenty- themes.
They’re pretty not common, other than WP 4.2.2. Two are on DreamHost under different user accounts, one is running on my Macbook.
There must be a commonality somewhere which is causing something to break.
Which PHP version are you using?
Can you check your PHP error logs for any relevant errors?
Are you sure no mu-plugins are active?
Are you using an administrator (or super admin on multisite) account?
Can you view the source of your page and check to see if any of QM’s output is at the bottom of the source code?