I have a laptop that uses Chrome and a desktop that on which I use Firefox. I added Chrome to my desktop and immediately started having that problem on both computers. I just deleted Chrome from my desktop and all the passwords are back and staying put. I have to use Chrome on my laptop, but not on this desktop, so I suspect Lastpass just got confused. It is still doing that on the laptop but that's not where I pay my bills. so I can live with it. I did report the problem however.
You saved the password to your browser's password manager, and it's overwriting the field. Go into that password list and remove the offending entry.
That does not work for me.
