Password forms wait for the page to be ready. On a slow connection, the sign-in page can appear a moment before it is ready to use. If you pressed Sign in in that moment, your browser could send the form in the page address, password included, instead of signing you in, and show you an empty form again. The sign-in, sign-up and password-change buttons now stay unavailable until the page has finished loading, which takes a fraction of a second on most connections.
No Google button until Google sign-in works. The sign-in and sign-up pages showed a "Sign in with Google" button before Google sign-in was set up, so it failed. It is hidden until it works. Email and password sign-in is unchanged.
No plan picker while plans cannot be bought. Monterva is in pre-release and takes no payment. The billing page now says so, instead of offering a plan that could not be purchased.
We found these while investigating failures in our own automated tests and reviewing the product, not from a report.