I've been using the autologin-and-lock solution as described in "Automatically login and lock" since Windows 7. Because I had a Pro license I used the gpedit variant, and found that the autologin was instantaneously followed by locking the screen such that the desktop wasn't even visible before the lock screen returned. However, I've found that on Windows 8.1 and Windows 10, the screen does not instantaneously lock, it instead idles on the desktop for 10-20 seconds before locking.
Is there a reason for this delay and/or can it be reduced/fixed?