Can't log-in, backup phrase not accepted

[elemonader]

Nothing is lost, I have backups elsewhere. But upon reinstallation after a factory reset (Android 11, Pixel 3A XL), I'm unable to access my storage/account. I'm ~99.9% certain that the passphrase words were input correctly. They were copy/pasted into a secure storage along with the login credentials.

I tried typing the words manually as well as copying them over. No dice. Any ideas? Obv you cannot provide the backup phrase. I'm just hoping to figure out what went wrong before upgrading and fully trusting the service going forward.