Bad field in a security advisory?

I’ve been getting some errors back from the securityAdvisories query and I’ve narrowed it down to one field in one specific advisory. The minimum query that errors is:

query { 
  securityAdvisory(ghsaId: "GHSA-fxwj-v664-wv5g") {
    severity
  }
}

With response:

{
  "data": {
    "securityAdvisory": null
  },
  "errors": [
    {
      "type": "INTERNAL",
      "message": "Something went wrong while executing your query. Please include `B642:3208:2EC7AE9:5583DB3:626732C2` when reporting this issue."
    }
  ]
}

All queries I’ve tried that include the severity field for that advisory fail in the same way, while queries without severity seem fine. Any suggestions?