Apple Battery Charger Not Charging Sanyo Batteries
Stating the obvious up front, the charger is only designed and tested to work with the Apple Batteries. It could be that the mAh of the Sanyo batteries is too different (out of range) for the Apple Battery Charger to properly recognize and charge to full capacity. The Apple batteries have a mAh of 1900. 

If the Sanyo are 2400 or even 1600 the gap may just be too much so that the charger doesn't do its thing. As long as the charger is still able to charge the Apple batteries, the charger should not be bum.