Hello @nicolasriani,
My name is Henry and I am happy to assist with your inquiry, and appreciate you contacting LastPass Support!
I am sorry about the issues you are having with your passwords. This is most likely being caused by your browser's in-built password manager. If you have stored your Master Password in your browser please delete it, then you should no longer have this issue.
Please let me know if this worked or if further assistance is required.
Thank you,
Henry | Customer Care