Reset problem of Ethernet board

I discovered an interesting reset problem with W5100 Ethernet board for Arduino nano. Made by "Deek-robot".
My sketch takes NTP time during setup processes. Everything worked fine, until I unplugged pragramming USB cable. Then it was not able to take time from NTP server. It worked, when I pressed RESET button.
So I guessed that during powering up RESET does not work correctly on Ethernet card. First I tried to use delays and added multiple attempts to get NTP time, but it did not work. So I added capacitor and resistors to RESET pin to prolong reset time. It worked. But then other problem emerged. It was impossible to upload a sketch as USB controller tries to reset processor. Seemingly my RESET delay was too long for sketch upload to work.
It is just for information for anyone if similar problem occur.