INA219: Writing to the calibration register sets unexpected bit to 0 (0x7B13 becomes 0x7B12)

Part Number:INA219

Hi, 

I am using this sensor for one of the projects I'm working on.

I know from the datasheet that FS0 from the calibration reg is always set to 0. However, my sensor is also setting the FS1 bit to 0 in some situations.

Eg. I write 0x7B13 to the calibration register, and after that, when I read this register, it's value is 0x7B12, thus, the bit FS1 was set to 0 by the sensor, as well as FS0.

I have verified that the write operation works. When , for example, I write 0xFFFF tot he register, the value saved is 0xFFFE, which is correct.

Am I doing something wrong?

Regards,