Problem about ADRF6801

we have designed a receiver based on ADRF6801 Quadrature Demodulator and we have a sort of problems with its SPI programming:

1-Register 4 shows an unusual behavior " when we write this register to its any valid combinaton which defined in datasheet, current consumption of ADRF6801 drops to a low current (50 mA) and

Pin-8 (MUX_OUT) doesn't work properly as defined in datasheet."

2-also when we write Register 6 current rises up to a random value between (130-260 mA).

does anybody face these problems!?