RX100 Mode dial error

I just found one strange problem with my RX100's mode dial and I am not quite sure whether it's a software issue or something else.

If I turn the mode dial in clockwise direction, everything works fine. But if I turn counter clock wise, the first click doesn't really change the mode, turn further ended up with the mode offset from the display. This problem can be work around by reverse the turning direction to clock wise, first click back to clockwise direction won't change the mode, which put the mode in dial in sync with the displayed mode.

Maybe it's a bug in firmware?