There are a lot of specs in the data sheet that could be confounding your tests. I recommend you study the whole data sheet very carefully. I’ve never worked with this particular part, and don’t have one to test, so all I can do is point out some of the data sheet specs that jump out at me as potential gotcha’s.
Power up time (Twu), 25 to 210 seconds. (you need a long wait after power up before readings are guaranteed to work)
Movement speed, 1.0m/s (hard to judge hand movement speed, try slower and faster movements)