Cisco AP 4800 (8.10) and Infoblox (7.3.2)

I ran into an incompatibility issue with Cisco AP 4800 (8.10) and Infoblox (7.3.2).
The Infoblox will not provide IPs via DHCP to these APs.
The same set up works fine with 3702s and 3800 series APs.

Performed the following troubleshooting test:

1. Connected a laptop to the same switch port and received an address on the correct VLAN / subnet = Infoblox is working correct for this scope
2. Created a DHCP scope on the same L3 switch that SVI resides for that VLAN, all APs got their IPs = the APs boot up process and DHCP request process works fine.
3. Tried couple different IPs for DHCP relay to Infoblox, I tried couple grid members as well as the grid master.

Let me know what you think...