I picked up a Nitecore UM20 exactly three weeks ago. I've been using it probably every other day, overnight to charge batteries. This morning I had a flashing error code. One battery was charged to 91% the other to 65%. They were at 50% when put on to charge so it's safe to say the error popped up not long after starting to charge. At this point it seems only the left slot of the charger is working. Has any one else had a problem like this or been able to resolve it? I went on their website and couldn't find anything relevant. I'd hate to throw this thing away after 3 weeks of use.