Default Screen turns off while gaming since update to 4.4

I've updated my LG G2 to KitKat Stock and now I've found that when playing some apps, the screen dims and finally turns off as if the phone was idle. In Android 4.2, if you were playing a game, the screen would stay on as long as the game was loaded, but in 4.4 it seems the thing has changed.

I haven't touched the screen timeout and its in the default value (30 seconds). Any idea if I have to configure something extra by my side or is this an issue with 4.4?

As a workarround, I can set a higher screen timeout, but the idea is to keep the screen on while gaming instead of just increase the timeout.
LG G2 | Stock 4.4.2
Samsung Galaxy S2 | CM11
HTC Desire | CM7
ASUS TF101 | KatKiss
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