This seems to be a common issue happening to G403, G603, G703 and maybe G903?
I contacted Logitech customer support and they are sending me out a new mouse, even though that it is most likely a software/ firmware issue.
The support person didn't really want to know the problem just that he was going to send me a new mouse to replace it.\
Hopefully they have a genuine fix soon as it is becoming really annoying.