1Password is filling in the wrong Secret Key

FWIW, I have exactly this same issue (and actually just sent support request about it). 🙂 1Password autofills an incorrect secret key that does not exist anywhere in my vaults. The correct key is stored in my vault, and I can copy and paste it manually, so account access is not my concern. But it is downright spooky and that 1Password autofills a Key of Mystery that doesn't seem to exist in any other context! Wacky!

And I can add a bit more: This has been going on for at least several months for me, and I’ve observed it on several devices, browsers, and with both 1Password 7 and 8. So it’s definitely not just an idiosyncratic configuration glitch on one device, or a bug with any version of the app or browser extension. The Key of Mystery is very powerful!