A network engineer manages a pair of Nexus 9000 switches configured as a vPC domain acting as the default gateway using HSRP. Users report intermittent connectivity issues when accessing servers behind a third-party load balancer and NAS appliance. Packet captures show these devices are sending traffic destined to the HSRP virtual MAC but also using the physical (burned-in) MAC address of the peer switches as the destination. Some of these frames are being dropped rather than routed. Which vPC feature should the engineer enable to resolve this issue?