Help! Drag and Drop functionality not working on subsites

I have a multisite network, and I'm experiencing a sort of unusual problem.

I have several plugins that utilize drag and drop functionality in the admin area (Nivo Slider, Admin Menu Editor). All of a sudden the drag and drop functionality became completely broken. When I click and try to drag, it pushes the other elements away from it. The more I move the mouse, the more the other elements move away. It's extremely weird, and the same exact thing is happening in both of the plugins above.

What's also weird, is this isn't happening at all for my main site. It's only happening on the subsites. I tried using the drag and drop in the those same plugins on my main site, and it worked perfectly.

Here's what I've tried:

I tried deactivating the Nivo slider (recently added) to see if it was conflicting, but still had the same result with admin menu editor.

I tried changing themes on my subsites, but still had the same result.

I'm not sure what to do next. Any help on this would be GREATLY appreciated!

Thanks,
Tim