I don't know if this is a modaco issue. However, I was on Jr7 for a month or so and i had no issues. About a week ago when i would unlock my phone it and the software buttons would disappear as well as the clock and i am unable to do anything. If i press the power button it turns the screen off. When i press the power button again the screen illuminates however has no display other than a black backlight. If i hold the power button it vibrates at me as if it is opening up the power menu. The only solution is to hard restart the phone.
This happens every couple of hours. Sometimes it will lock up during charge and other times it will lock up while using any app. I thought it might have been Jr7, I updated to Jr10 and i still had the same problems. I tried Cyanogen Jr9 and still the same thing (dirty flashes). I have a feeling it is system ui that is failing.
I suppose the next couple of options are try stock or a full wipe and see if that fixes it.