This problem occurs only when Caps Lock is turned on while NoMachine is connected to the Windows login screen.

Steps to reproduce:

1. Connect to a Windows 10 host by NoMachine.

2. Lock the user's Windows desktop inside the session.

3. Turn Caps Lock ON.

4. Type the password to unlock the screen: letters in the password don't have the correct lower-case or upper-case format and the "Caps Lock is On" indicator pops-up each time a key is pressed.

5. Correct lower/upper case for the password and log in with Caps Lock still ON.

6. Keep Caps Lock ON and type something for example in a text editor: letters are randomly lower-case or upper-case.

Summary: Resolved in version 6.10.12 released on 2020-05-12.