When I configure a single-hop ipv4 route using the Postman request "add single hop ipv4", it results in:
sudo vppctl show fib paths
[@0]: dpo-receive: 16.0.0.1 on GigabitEthernet0/8/0
index:22 pl-index:22 MPLS weight=1 attached-nexthop:
192.168.2.8 local0
[@0]: mpls via 192.168.2.8 local0:

When I apply the same configuration using VAT:
vat# ip_add_del_route 192.168.2.3/32 via 192.168.2.8 vrf 1 sw_if_index 0

sudo vppctl show fib paths
[@0]: dpo-receive: 16.0.0.1 on GigabitEthernet0/8/0
index:22 pl-index:22 ipv4 weight=1 attached-nexthop:
192.168.2.8 local0
[@0]: ipv4 via 192.168.2.8 local0:

This causes VPP to attempt arp-mpls resolution of the destination address, instead of forwarding packets to next-hop.