I noticed something interesting recently:
Like many others, in normal operation my battery meter jumps from full to depleted, giving me maybe a minute notice with the half battery indicated.
But, if I have the grip attached and one battery is depleted it shows the half battery. When I remove the grip (depleted battery is in the grip) and turn on the cam again, it shows the full battery. When I then screw on the grip again (with depleted batt) it jums straight back to half depleted..
My guess would be that the battery indicator is not faulty or buggy, it's programmed for a two battery system...
Any thoughts?