Hello,
These pins must be leave unconnected since these pins are used for factory calibration, you must not connect to external circuitry or ground, otherwise you will probably change the calibrations values causing a malfunction of the device, or even worst, the device could be permanently damaged.
So, as I mentioned before, I do recommend leave these pins unconnected.
I hope this information will be useful for you. I am glad to help.
Best regards,
David