DS3231 read date error

[opentld]

I am having a problem when using the DS3231 clock module: I can read and write the RTC clock module normally, and I connect the RTC clock module to the Raspberry Pi, reboot the Raspberry Pi, the date read again is wrong, not the time that I previously written in.
But as long as the Raspberry Pi does not reboot, the time I read and write is correct.
Have you encountered this problem?
@leinardi