In the Android4.4 hwui, i get the opengl error log:
GL error from OpenGLRenderer: 0x0506
The error is the GL_INVALID_FRAMEBUFFER_OPERATION, i think maybe there is some error in the fbo, but the android hwui code, we did't modify it.
The error will make the Launcher icon draw error, or make the icon is black, but the error is not easy the appear, also I have not idea how the make it reappear, it will appear inadvertently.
from Android bug——Launcher 0x506.Hope it can lend you a hand. :)