DHCP on SBS 2003 - BAD_ADDRESS in DHCP lease list

I moved the DHCP to the SBS, instead of leaving it up to the router. I set the scope to 192.168.0.110 to 220, where the router had it 100 to 190. This was done to rectify the issue with the server being locked at 100 (because it's easier to remember when going in on remote). Immediately after the new scope got activated, I have an entry in the lease
list as follows:

192.168.0.120 BAD_ADDRESS 7800a8c0
"This address is already in use"

According to this I know that the MAC is having 4 digits less but what does that means?

When I had this problem I manually went to each client workstations and did ipconfig /release all to clear old leases and then do an ipconfig /renew. You should try out the same. Let me know the results.

Well, that was the thing, I couldn't find anything that matched that messed
up MAC. Today however, the BAD_ADDRESS entry is no longer there. So I am still clueless as to what caused it. I haven't figured out how to access the DHCP log yet, but atleast now the DHCP appears to work.