I have purchased a Liberty 4 NC and have a problem with the noise cancelling. It worked at first. Yesterday I was using my headset and I heard a ‘pop’ sound in my left ear, and it started with a permanent white noise. It is only on the left side and only while NC or transparent mode is switched on. Shortly before it had installed fw 3.86 and then fw 4.86.
At the moment the most silent option is to switch off noise cancelling at all … On all NC modes I have the noise on my left ear.
Try restarting your device
I’ve watched The IT Crowd, so I’ve done so 
. Three times, I have restarted ones after each fw update and one extra time. (Before the fw updates the items were fully recharged and remained in the box). I suppose the left ear thing has a hardware failure somehow. I will have to return it.
Bogislav, did you found a solution. Just had the same problem with the right earbud (same model). Listened a pop and then a bit of white noise while the nc or transparency mod are on.
I have returned them. It was a failure in the electronics. I think the pop sound was like something “burned through”, a chip started to fail or so. With my replacements it works great.
I got the same issue, I tried to order a second device but I found the same issue. Any clue?
I am facing the same issue, 2nd day after received it 
My liberty 4 NC have the same problem (right side). Is there any other solution without returning them