HSRP Version 2 and DHCP doesn't work well with ARPing.
I have my N7K and setup the following per what I believe is recommend design:
Core1-N7k is Primary as VPC peer, HSRP Version2 Active, STP root. My OSPF is set to Point to Point so no need to worry about DR and BDR. I have also setup a separate LACP for VPC VLAN versus another LACP for non-VPC vlans.
I have a VPC to a 3750 switch set to "spanning-tree port type normal" where all my HSRP/VLAN 2XXX is going through. Host sometimes can get DHCP or not, when they cannot I find there is an arp issue so need to bounce the vlan interface on the N7k to get it working but this is a bandaid.
I heard if I enable "Peer Gateway" on both N7K cores, this may solve the problem but create additional problems. I will probably try this but wondered if anyone had the same problem or a solution.