A common problem that causes the Real Time Clocks (RTC) running slowly or incorrectly is the crystal.
Check crystal characteristics such as nominal frequency, load capacitance, serial resistance to make sure that they meet the requirements specified in the datasheet.
After that, check the layout to make sure that the crystal is connected to the RTC with short and wide traces to minimize stray/parasitic capacitance.
If the RTCs support square waveform output, users can probe this output to verify the crystal frequency. This is a useful feature for debugging.