I have experienced this bug and read about it many times on various forums online, so I'm a bit angry that it hasn't been assigned a higher priority. It essentially makes the Firefox extension unusable and requires you to access the site in order to log in. I will most likely be changing password managers if this continues.
The bug involves clicking on the the browser extension, and then having it immediately close as you click the "Enter password" field. This has happened to me in Firefox on Windows and Ubuntu. It is extremely frustrating and makes the extension essentially unusable.
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