Do you check BIOS/UEFI configuration?
Restart your computer and access the BIOS or UEFI settings by pressing a specific key during startup (e.g., F2, Del, or Esc). Navigate to the Keyboard or Function Key Behavior section and look for an option to change the Fn lock behaviour. The specific option and location may vary depending on your computer's manufacturer and BIOS/UEFI version.