Odd behaviour with Google Chrome and Django admin

I was filling out some model data using the Django admin on Google Chrome, when I suddenly started getting 502 (Bad Gateway) errors when trying to save edits.

Oddly enough, it works in Opera or in Chrome (incognito mode). I've only a few extensions enabled:

So I'm really wondering why I'm having issues. If you figure anything out, please let me know.

Update: I restarted Chrome without extensions, and it worked for a while, then gave the same problem. I was using incognito mode, and then it gave the same issue:

So, it's back to Opera for now.

Update: it's started in Opera too.