Placeholder value in sandbox annotation doesn't work

Cause the following:

Invalid value placeholder specified for annotation run.googleapis.com/sandbox. Allowed values are 'gvisor' and 'minivm'.
Details:
[
  {
    "@type": "type.googleapis.com/google.rpc.BadRequest",
    "fieldViolations": [
      {
        "description": "Invalid value placeholder specified for annotation run.googleapis.com/sandbox. Allowed values are 'gvisor' and 'minivm'.",
        "field": "spec.template.metadata.annotations"
      }
    ]
  }
]