EDIT EDIT EDIT: See post 16 for explanation of the cause, and a possible solution
I have mentioned this in a few conversations about network issues, but I don't know if DJ saw it since the issues were marked a resolved before he commented, so I am opening an explicit thread for this bug report.
While troubleshooting some strange issues on my 802.11g and n network when running multiple EZ-B's (specifically, EZ-B's and the few other G or N devices I have refusing their reserved IP addresses and getting other addresses, not showing up in the DHCP client list of my router, and some strange error messages in the router log) I ran wireshark on a computer connected to my 802.11n network with a display filter looking at bootp messages then powering on EZ-B's.
The first EZ-B come up normally and connects to my network with normal messaging.
When I power up the second one, and it sends out a discover, both my router, and the first EZ-B send out an offer. The EZ-B accepts one of the offers (usually the one from the first EZ-B), and rejects the other (and the router sends out a reject and logs an error because it is seeing another DHCP server on the network).
When I power up a 3rd EZ-B, the first 2 send offers.
4th EZ-B, the first 3 send offers.
Any other device also get DHCP offers from the EZ-B's as well as the router.
Thankfully most of my network is on 802.11ac or wired and not impacted by this, but the few 802.11n devices behave very strangely when the EZ-Bs are on (losing their internet connection, or restarting their network connections).
Hopefully this will be an easy firmware fix, because it is actually fairly serious and unfortunately validates the few network administrators who have told users here that they can't put the EZ-Bs on their networks. Having more than one DHCP server on a network is a major networking policy violation.