AWS AppSync VTL resolver but got "RequestFunctionEvaluation" (JavaScript) error

{ "logType": "RequestFunctionEvaluation", "path": [ "listMeshpkgs", "items", "1", "id" ], "fieldName": "id", "resolverArn": "arn:aws:appsync:ap-northeast-1:993295166108:apis/so65etifdrf4vdan5uoi27fdr4/types/Meshpkg/resolvers/id", "requestId": "65aeca92-c905-4d57-99b6-942cab9b883d", "context": { "arguments": {}, "source": { "uid": "", "port": 4, "from": -1118135392, "id": "1720745960712", "to": -1118149240, "packet": "from: 3176831904\nto: 3176818056\ndecoded {\n portnum: NODEINFO_APP\n payload: "\n\t!bd5a9ba0\022\017Meshtastic_9ba0\032\0049ba0\"\006\020\227\275Z\233\240(\004"\n request_id: 1401860457\n}\nid: 1814115987\nrx_time: 1720745959\nrx_snr: 7.75\nhop_limit: 3\nrx_rssi: -77\n" }, "stash": {}, "outErrors": [] }, "fieldInError": true, "evaluationResult": {}, "errors": [ "Value for field '$[operation]' not found." ], "parentType": "Meshpkg", "graphQLAPIId": "so65etifdrf4vdan5uoi27fdr4" }