AWS v1.3.2 Dual NIC deployment eth0 (Public with EIP) & eth1 (Private)

Scenario: Experiencing connectivity issues due to eth1 interface default route taking precedence.

After the initial deployment, I have been able to ssh onto the EIP. I check the host route table and the private interface has been selected as the default gateway. I then reboot the host and lose all ssh/ping to the EIP.

Has anyone come across similar? I have tried a number of variations of interface role & even creating both interfaces outside the ‘instance’ module via terraform but still experience inconsistent behaviour.

both interfaces are being installed with the same metric which I have been unsuccessful in modifying via cloud-init.

Appreciate any insight