Hello,
I have this issue, when I attach (hdmi) an external monitor, the fingerprint reader is not initiated ~95% of the time. Using Meta+L it's usually working, but on closing lid (on charger, so it does not go sleep only locks screen) or just waiting till timeout locks the screen usually end up in the fingerprint reader not working on login.
Tamás
Ps.: Please let me know what log files or config would make it easy to identify the issue.