After Sierra Update:Trackpad Not Disabling with Magic Mouse Connected

Hello,

after i updated to macOS Sierra on my MacBook Pro the Trackpad is Not Disabling with Magic Mouse Connected.

Device: MacBook Pro Retina 15-inch (Late 2014) on macOS Sierra.

Since updating, I've noticed that my built-in trackpad stays enabled with my Magic Mouse connected after the login window.

In System Preferences -> Accessibility -> Mouse & Trackpad, I do have "Ignore built-in trackpad when mouse or wireless trackpad is present". If I toggle it off and back on again, the setting will hold.

However, once I lock the device (username on top right -> Login Window...) and log back in, the trackpad works. You have to toggle the setting every time.

Is this a macOS Sierra bug (can't seem to find anything about it) or am I missing something? I'm aware that the trackpad is re-enabled at the login window but before it would disable itself after logging back in.