G2 not registering the second touch when playing games

Hey guys. I'm asking to find out if anybody else has experienced this and if there's a fix for it.
The first time I noticed this problem was when I changed the settings in the game 'traffic racer' to manual speeding and touch steering. It would play well for some time, but then it would stop registering the second touch sometimes, so you would have to touch it twice or thrice for it to register. I thought the game was badly coded, but today I downloaded Real Car Drift Racing and with manual throttle and touch steering and the same problem occurred. The phone won't register the second touch.
I tried updating touch firmware in hidden menu, tried to see if the phone registered all my touches in the hardware test and it did (but I won't do it again since I don't know how to get out of it without rebooting).

I'm stock unrooted D802 running the 20D firmware. Thanks in advance.

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I'm using a 35 dollar tempered glass screen protector - it could be that my fingers get sweaty and that's what causes it.

I don't use knock code =) it's too inaccurate for me and the fact that the LED doesn't light up when the phone is unlocked bothers me =) thanks for your responses.

Sent from my LG-D802 using XDA Premium 4 mobile app

The problem seems to be heat. The g2 has problems detecting a touch when the area is hot. This could be due to the glass screen protector, but it's definitely annoying.

Sent from my LG-D802 using XDA Premium 4 mobile app