Yeah I read about that looking for a solution! But it was not necessary to change the protector (which don't have cut-outs) I just re-calibrate my proximity sensor. I followed a guide I found on XDA:
1. Opened stock dialer.
2. Dialed *#546368#*810# then Hidden Menu screen showed up.
3. Selected "Device Test"->"MT", it showed "system will be restarted", then OK.
4. After beboot, GENESIS MiniOS 3.1 screen showed up, pressed "individual item+power" while power button was pressed.
5. Next, went to "sensor test". In that moment I didn't block the proximity sensor and waited for the proximity sensor to be automatically calibrated. Then I needed to block proximity sensor two times to exit (In this step, I assured if the proximity sensor was working correctly "zooming in and out" my hand and checking the numbers shown)
6. Went to "Back to the MainList".
6. Pressed "Normal boot+power" while power button was pressed again to reboot system, done.
MARSHMALLOW's PROXIMITY SENSOR BUG fixed!!
