I was wondering if someone has encountered a similar problem to what I have. I have created a simple live wallpaper (starfield effect) and most of the time it works fine on my android 7 device and other devices the problem appears more often.
When previewing the wallpaper it is always rendered correctly but after applying and going back to the home screen the stars will be drawn black. I have tried drawing large static boxes and ellipses on the screen with static colours like red, blue etc but they are also drawn black. The stars are also large like stroke has been enabled even though I have set to noStroke.
On an older M8 (android 5.01) It happens consistently but if I set the wallpaper so its not working and then simply rerun the sketch it will correct it and it will run fine until the phone is restarted or wallpaper is reselected. My android 7 phone will fix the problem with a restart.