Unless there's a JS conflict breaking the K2 backend (e.g. via a 3rd party extension), ordering should work just fine. A screenshot or screencast would certainly help me see how the issue specifically occurs.

Sorry, the screenshot is low-resolution and I can't see much. There is a JS error for sure (some inline JS code). Can you upload a higher-res image e.g. on imgur.com please?

The "K2 - System" should not be disabled by the way. This comes from K2.

What I meant is look for third-party extensions that interface with K2 or other system plugins which may inject code on all Joomla pages in the backend...

Again, I'd need a screenshot for that to see if there are any JS errors.

Ordering works just fine on my end and my demo site uses 5 languages.

Locate that line please. When you click on the URL on the right, it should load up the actual HTML line.