I made the board, but I think schematics is the same at the RTC chip. See attached.
Experience: after NTP sync, NTP swiched off. Power off.
After re-connecting, behavior seems to be always the same. Depending on the time of the re-connection, it jumps back an hour, then starts to go backwards.
What I have already tried:
– built a new board with all chips new
– re-burned the firmware
– checked with oscilloscope that 32kHz clock is working
What else to check?