I'm seeing a hilarious bug where QB online asked me to log in within it's own interface and now the left menu is duplicated. No way to report bugs I'm mentioning it here.

This isn't the experience that we want you to have, @fletcher-kitsapp.

I'll help you sort things out so you can avoid issues on your QuickBooks Online interface.

Sometimes the historical data stored for a long period of time can cause trouble on your browser. I suggest performing some basic troubleshooting procedures to verify if you're experiencing a browser-related issue. Start by accessing your QBO account using an incognito browser. 

Use any of these shortcut keys to open it:

• Google Chrome: press Ctrl + Shift + N.
• Mozilla Firefox: press Ctrl + Shift + P
• Safari (new versions) : press Command + Shift + N

This time, try to check the Left menu and see if it's not duplicated already. If so, then you'll have to clear your regular browser cache to avoid unusual browser behavior moving forward.

If the issue persists, I recommend using other supported browsers.

We'd also appreciate it if you provide us with a screenshot or any additional details like error messages that you might have encountered.

For future use, here's a guide on how you manage users in QBO: Add and manage users in QuickBooks Online.

Don't hesitate to message back if you have additional concerns with this matter or QuickBooks. We're here to back you up 24/7. Please keep safe!