I observe too late pull down gesture blocking when switching on Touchscreen Lock.
I faced it trying to clean screen (swipe from top to bottom) just after pressing power button to lock touchscreen.
Following steps show the issue:
1. Start activity recording
2. Press power button to lock touchscreen.
Message "Touchscreen locked" show up at the top of the screen.
3. Do swipe gesture from top to bottom of the screen while "Touchscreen locked" is displayed at the top of the screen. Status menu will pull down.
Such swipe gesture doesn't work after "Touchscreen locked" message hides.
Any tap on the screen is blocked while "Touchscreen locked" is displayed except gesture to pull down status screen (swipe from top to bottom of the screen). Once pulled down it can't be pulled up as software buttons are already blocked.
I think there is bug in the code that enables touchscreen lock mode. Gesture is blocked after message is hidden but should be blocked immediately after power button press as it is for all software buttons on the screen.
Do You experience the same?