OK so you are using different VRFs... that is key information here.
Is the DMZ interface in VRF 1 or 0?
Why are you using VRFs?
Why are both your WAN IPs in the same subnet? Are they actually different circuits or is it a single shared circuit that you are trying to use differetn IP addresses on?
If it's the latter, you do not need to use multiple interfaces. Just have your primary WAN interface with IP address X. Then use VIPs for the other public IP addresses you own. They will enable ARP on the WAN interface to respond to those other IP addresses.