[CORed]

If the problem never occurs with standard batteries, this would seem to indicate that one or more of your rechargeables is bad. As a start, I would suggest that you number your rechargeables or mark them in some other way that uniquely identifies each battery, and see if one or more particular batteries cause the problem. Also, make sure you are fully recharging the batteries. I don't know whether your charger has some type of indicator for a full charge, or your just rely on them being in the charger for a minimum amount of time, but it's possible that a less than fully charged battery is causing the problem. However, the type of problems you are describing seem more likely to be a symptom of an intermittent contact somewhere, either in a battery or in the mouse.