The agent-tui interface for editing the network config for the Agent ISO at boot time only runs on the graphical console (tty1). It's difficult to run two copies, so this gives the most value for now.
Although tty1 always exists, OCI only has a serial console available (assuming it is enabled - see OCPBUGS-19092), so the user doesn't see anything on the console while agent-tui is running (and in fact the systemd progress output is suspended for the duration).
Network configuration of any kind is rarely needed in the cloud, anyway. So on OCI specifically we mostly are slowing boot down by 20s for no real reason. We should disable agent-tui in this case - either by disabling the service or simply not adding the binary to the ISO image.