This sounds like a possible bug introduced in Firefox 151.0.1 rather than an issue with your authenticator app. Since TOTP works fine in Safari with the same codes, it suggests the tokens are being generated correctly, but Firefox may be rejecting them due to a time sync issue, cached session problem, or a validation bug in the latest update. You could try checking system time sync, clearing site cookies/cache, or testing in a private window. If the issue persists, it’s worth reporting as a regression to Mozilla since multiple users may be affected after the update.