MPU-6050 Not outputting data as expected

Hi
I've got 25 boards back from the assembly crowd. They have has a MPU-6050 Gyro/Accel on the board.
A fairly high amount of the boards, (11/25), The MPU-6050 chip is not sending the correct data back to the micro for processing. The AccelZ MEMS data and the Temperature data is stuck on 0.
I can communicate to the MPU-6050 correctly as I can request the ID address (&H75) and it replies with the correct data. I can also read the PWR_MGMT_1 register and it replies with the correct data.
I'm resetting the device as part of the INIT startup. I'm missing something obviously simple, as I can get other boards running correctly with the same code. Is there a factory setting that I'm missing that need to be added..