I appreciate you for sharing your experience in reconnecting an online bank account in QuickBooks Self-Employed (QBSE).
Unexpected behaviors in browsers are usually caused by its cache. To isolate this, I suggest opening your browser's private window. Shortcut keys are listed below:
Google Chrome: Ctrl + Shift + N
Microsoft Edge: Ctrl + Shift + P
Firefox: Ctrl + Shift + P
Safari: Command + Shift + N
If that works, go back to your regular browser and clear its cache. Otherwise, open a different browser that's available.