This morning I got a complain that a computer is not connecting to the network at one of my sites. Wghe I went there I realized that the PC cannot get IP address. When I went to the local DC and checked the DHCP I saw a lot of BAD_ADDRESS records with strange MAC address: They were something like 4850006a, 4860006a, 4870006a, etc. and they were like 50 or more of them. I was checking the other DCs and everything looks fine. I have not changed anything on the DCs, just start happening.
I have 4 2008 DCs on three sites and they are in the same forest. Let me know if you need more info.