So we have two R2 units we built at the Droid Depot. We found when the batteries get low the head has trouble tuning to the right. It continues having this issue even after we change the batteries with new ones. Somehow, one of the droids just started to work again and the head is acting normal, but the other is still moving very slowly to the right and normal speed when the head turns left. Has this happened to anyone else? Clues on how to fix this?