It doesn't go back specifically.
How it works is by redirecting the electrical current from your finger to the top part of the screen where for example in the screenshot of tapatalk you see cancel top left and reply top right.
So in this case if you pressed bottom left you would be triggering cancel and bottom right the reply button.
The problem is the electrical current it is simulating narrows and the touch margin reduced which means more often than you would like it doesn't recognise the press accurately. You end up then pressing harder or multiple times to trigger something that would have required a single press before.
Likewise in the top area where you would press those buttons yourself the screen protector creates a little deadzone.
It's a fantastic idea in principal but in practice there is a reason all the screen protector manufacturers aren't implementing it as standard.
I stuck it out for a week before I just went back to a standard glass protector.