We had tested it and found it just a system software bug, and the factory provided us a new firmware to solve this problem.
Sorry for the inconvenience brought to you.
Due to difference firmware version between the android unit, you can go to the Settings--About device--version info to check your current system version.
When you post the same problem on our forum or contact our customer service to get the right firmware for your unit, please attach this information to help us check.
Here is a picture for your reference.
- version info.png (89.21 KiB) Viewed 32222 times