So, it turns out that the white light does not mean GPS lock. If the back light is blinking a color (not white), it means it is searching for GPS. If the color is solid, that means it has a GPS lock. What the white means is that it is refreshing the location of the ST-16 for when you RTH. For those who do not know, the H has Dynamic Return to Home, which means the H RTH's to where ever the ST-16 is. So if you move while flying the H has to update its RTH position. THAT is what the white LED is doing.
Explanation of the white light begins at around 9:00
Explanation of the white light begins at around 9:00