An administrator sees the following output from 'get router info routing-table':

S       0.0.0.0/0 [10/0] via 192.168.1.1, port1
S       0.0.0.0/0 [10/0] via 192.168.2.1, port2

They have configured ECMP load balancing. However, traffic to a specific destination IP is always using port1. What is the likely reason?