I found the answer in another user's question that was similar - remove the LastPass password from the browser password manager. Hope this helps someone else.
My system is populating every password with my Master Password for LastPass - how can I stop this? If the answer is the above, how do I remove it from my browser password manager?
Hello @Mike Sisk
In your case, remove any LastPass entries in your browser's password manager, and/or disable it.
Thank you,
Karol | Customer Care