Others are getting it, no definite answer. https://forums.lenovo.com/t5/DROID-ULTRA-ULTRA-MAXX/wifi-indicator-turned-white/td-p/2954746 Some say it is white when connected to router but blue when connected to google serves but not sure if that is true.
Mine does the same, and it is just to contrast with the background so you can see it.
Oddly though the triangle showing mobile signal strength doesn't turn dark on a white background, so it seems to disappear.