There's a problem with the QR code scanner with Twitter. I turned on 2FA, scanned the barcode, and no matter how many times I tried it I couldn't log in without using one of my backup codes. I tried to set it up again tonight twice, and the 2FA codes generated by the QR code just didn't work. I tried the alternate method, which gives me the secret code - and I put that code into the OTP URL string manually, then it worked to properly generate the 2FA auth code.
So I'd encourage the 1Password developers to take a fresh look at how the QR scanner works with Twitter's 2FA system.
1Password Version: 7.6
Extension Version: Not Provided
OS Version: macOS 10.15.6
Sync Type: Cloud
Referrer: forum-search:macos twitter 2FA