Log out of the site - refresh the page - as doubleclick, and google-analytics are loading - click in the password box and start typing - password will be visible. This is mainly going to affect people with slow connections, or if something is taking a long time to load. If the site loads fast, your never going to notice it. Once the site has fully loaded - password will not be visible. This is a hit and miss situation, as you have to start typing your password while the site is still loading - this includes all external scripts.
The only thing I can think of is the JavaScript for the page never was able to finish running. If you don't have JavaScript enabled, the password field will be readable because of how it labels it as "Password" within the input field itself. There is a JavaScript event that alters it when the input gets focus. I would imagine there is a LOT of strange things happening if you disable JavaScript somehow.