Camera freezes in Skype

I have two Teclast Air II tablets, models HG9M and HG9N. Both have Mirek's Android 5.0 ROM v5.0 installed. Both have the same problem:

When using Skype, the front camera freezes pretty frequently, usually after a minute or so. Sometimes restarting Skype helps, sometimes reboot is required to "unstuck" it. I wonder where the problem might be, is it Skype being buggy, or Android, or faulty hardware? Does anyone else have a similar problem? Anything I can do to resolve/troubleshoot this issue?

Strange freezes with Z5

I've had the xperia z5 for one day now and the phone has been great, however when i'm watching twitch or YouTube the phone can freeze. In the case of twitch the app just crashes and I need to go to the homescreen, close the app and restart it. In the case of YouTube it just pauses. These freezes usually happen every 5 minutes or so and are very annoying. If i'm wearing my headphones I can hear a beep right before it freezes. The freezes also happen in other apps, but there they just feel like they is some lag, however in videos it is very noticeable. I've already uninstalled all possible apps, but the problems remains when watching youtube videos.

Does anyone have a solution to this problem or do i just have a defective unit?