Since WP 5.1, last password not remembered

Hello,

Since WP 5.1, Private Site always shows the login screen, but the password is always wrong. I have to ask for an email every time. Once the password reseted, it’s OK until the next reconnection.

Is there any way that the right password is remembered?
It’s to avoid asking for a reset password mail every time.

Before WP 5.1, it worked fine.

Private Site is not alone. I tested various such a plugin, and always the same problem.

Does WP 5.1 change any thing about that?

Thanks a lot,
Jean