Hi Patrick,
1. Leakage current on the CP5 pin should be kept to a minimum. All sources of leakage, including reverse leakage current through the diode and PCB surface leakage should account for not more than 70uA. For most applications, the diode is the primary source of leakage current.
2. Applications that operate at 3.3V should use an inductor value of 560uH to ensure proper operation of the internal boost regulator. For all applications, the inductor should be capable for 50mA of peak current.
After you pay attention to the two items above, I think your problem should can be solved.
Hope these can help.
BR
Neil