The issue seemed to be occurring as we utilize 2 networks in our definition of the machine, so while trying to attach floating IP to the machine it was getting confused by which network interface (external or internal) to connect the floating IP. Instance_floating_ip_net allows us to tell the packer to only attach the floating IP to the external network on the machine. That seems to have resolved the issue, as we haven't seen it happen in the last 10-15 runs.