Good: M63 stable on eve (63.0.3239.116)
Bad: Chrome OS 64 beta channel on samus (don't have the machine on me, sorry)
Bad: ToT linux-chromeos r528837

What steps will reproduce the problem?
(1) Lock the screen (or go to login screen)
(2) Type your password, don't hit return yet
(3) Hit return and watch the password field closely.

What is the expected result?

Password field keeps "*****" characters, so there's no visual motion at the center of the screen during the unblur/fade animation. The caret should disappear.

What happens instead?

The "*****" characters vanish and the help text "Password" pops in. Also, the text insertion caret stays at the end of the word "Password", even though when you're at the login screen with the field empty the caret is at the front. (In ToT the caret moves to the start of the field.)

See video: https://photos.app.goo.gl/IptzFeh3tJDkcmyl1

I suspect this could be fixed by just not clearing the field when the user hits enter.