What could cause the STC3115 to ACK data but not save it to memory?

[CBrow]

I'm using the STC3115 driver provided by ST and am having a strange issue with the STC3115 on a custom board. I've hooked up an o-cope and am monitoring the data being sent over I2C. When I write any of the registers in the STC3115 it ACKs the data but when I read that same register the data has not been saved. I've see that the battery detect feature can cause strange behavior but the driver is reporting that the BATFAIL bit in REG_CTRL is not set so I don't think that's the issue.

Any help would be appreciated.

Thanks!