Confidential AI 3.21 is a stability release. There are no new features or bug fixes since 3.19.
Fortanix has a fair usage policy in this Early Customer Access Program. Hence, Fortanix has limited the resources one can create per account. Therefore, it is expected to observe a resource creation failure message once you have reached the max limit.
To report an issue/bug, visit https://support.fortanix.com/hc/en-us/requests/new.