inconsistent strings used in /proc/cmdline to detect fast reboot.
dockers/docker-orchagent/swssconfig.sh uses "fast-reboot" to detect fast reboot

Looks like SONIC_BOOT_TYPE=fast is the string that is saved by sonic-utilities:scripts/fast-reboot file

Correct usage
docker_image_ctl.j2 checks for "SONIC_BOOT_TYPE=fast" in cmdline