I had a problem when I went to add a 10g NIC to my server. UnRaid seems to have a problem getting it's main internet connection from anything other than eth0. I wound up changing the mac addresses in Network Settings to give eth0 to one of the two 10g ports on the second NIC and eth4 to the original port on the original NIC. I noticed today actually, that my ntp service had stopped working since that very day and my logs show the same as @tetrapod. I am at a loss with what to do now short of keeping an eye on the time manually.