W5500 unexpectd reset

Hi all, I developed two different cards AtMega2560 based, using ethernet2 TCP/IP library. Both cards use W5500 ethernet shields.
We are experiencing some random W5500 reset. After 3-4 days or some, the chip stops responding. We have a serial interface with a CLI and we discovered that all the W5500 parameters come to the default value (IP= and so on). The W5500 rst line is pulled up by a 10k resistor to the shields 3v3 Vcc, and it is pulled up to Vcc (5Vcc) also on the board.

Should be this the problem?

Thanks a lot