It appears that the DS2715 does not enter Discharge mode. Why?

The DS2715 requires that voltage across the sense resistor exceeds VDCHG-SET which is 15mV maximum, 5mV minimum as specified in the datasheet. A common sense resistor value is 100mohms. This would require 150mA to generate at least the 15mV  that the DS2715 requires to enter the discharge mode. Due to DS2715 tolerance VDCHG-SET  can be as low as 5mV. If the voltage across the sense resistor is insufficient, the DS2715 will not transition states until the voltage reaches the correct level or a timeout occurs. 

Polarity for this is positive for discharge current and negative for charge current

To exit the discharge mode, either power must be cycled or a charge power source needs to be connected that will cause at least -15mV to appear across the sense resistor, and the DS2715 will enter the PRESENCE mode to start another charge cycle.