Polycom 430 DHCP Duplicate IP message

Hi All,
This probably isn’t the best place to ask, but I can’t find the answer anywhere else.
I have some Polycom SoundPoint IP 430 phones that I want to deploy into the field.
In house I have an Asterisk 1.4.x server on CentOS, handing out config info via dhcp.
I need to configure the remote phones to use any old DHCP server available, to just get an IP address and gateway.
I’ve already configured the rest of the info (Asterisk server IP, Proxy server IP, etc.).
The trouble is that when I set the IP to DHCP, the phones boot up, but constantly give me duplicate IP addresses and show MAC addresses of other devices on the target networks.
The problem is, those devices don’t have the same IP address at all.
Very simple networks here. No VLANS, no multiple segment networks, etc.
I did find a thread on a TrixBox forum suggesting it might be a BootROM/firmware problem.
I’ve upgraded the BootROMs to 4.2.2 (latest supported by the 430’s) and SIP from 1.x to 2.2.2.
Still no luck.
I really don’t want to have to configure each phone with a static IP from each remote network.
Any ideas will be greatly appreciated.