FreeBSD 12.2-RELEASE x86_64 EC2 AMIs in us-east-2 not booting

Thu Apr 1 21:58:06 UTC 2021

I've attempted to provision x86_64 instances in AWS region us-east-2 from both the Marketplace AMIs and the specific AMI ID provided by the 12.2-RELEASE announcement, and they just get stuck in an endless boot loop. Appears to load the kernel, then reboot instantly. Are there any known gotchas about provisioning this release or anything I can do to get these running?