RP2 - freezing with double tap to wake/sleep on

I have bought the RP2 a month ago and the phone sufferered from random freezes followed by reboots since. Since i was used from me previous phone to wake the phone and also shut the screen off with double tap i have activated the functions under settings->display->advanced "double tap to wake" and "double tap to sleep" and also in Nova Launcher settings->Gestures->Double Tap to "screen lock". With this settings on the RP2 behaved exactly as i wanted (as i was used to with my previous LG phone). But once or twice a day the phone became unresponsive just while lying on the table. When i wanted to wake the phone with double tap nothing happened, also the on/off switch was not working. And then maybe after a minute the phone rebooted itself. And this was the scenario day by day. I have than made a stress test and was double tapping the phone a lot of times. I could actually observe that after 5-10 times of waking the phone the double tap started to be sluggish. I double taped and nothing happend but with the second one the phone waked up. But than after few more rounds the phone frozen. Since i turned this settings off, the phone does not freeze anymore.