Screen not turning on when receiving calls

Whenever I receive a call, the screen does not turn on unless I hit the power button to mute the call, eventually it turns on. Even when using the phone, a call would show the heads-up notification and it seems like the entire phone lags. Hitting the answer button takes at least 1 second for the call the to be receieved and even longer for the screen to switch to the calling screen. I am on CM12.1 0904 with ak303 and a custom profile for the kernel.