AWS CDK: deploy error "Error reason: EXACTLY_ONE_CONDITION_REQUIRED, field: MANAGED_RULE_GROUP_CONFIG, parameter: ManagedRuleGroupConfig"

import * as cdk from 'aws-cdk-lib';
import * as wafv2 from 'aws-cdk-lib/aws-wafv2';

export class CdkWorkshopStack extends cdk.Stack {
  constructor(scope: cdk.App, id: string, props?: cdk.StackProps) {
    super(scope, id, props);

    // defines an AWS WAFv2 WebACL resource
    const webACL = new wafv2.CfnWebACL(this, 'WebACL', {
      defaultAction: {
        block: {},
      },
      scope: 'REGIONAL',
      name: 'waf-sample',
      description: 'this is a test',
      visibilityConfig: {
        cloudWatchMetricsEnabled: true,
        metricName: 'WebACL',
        sampledRequestsEnabled: true
      },
      rules: [
        {
          priority: 9,
          name: 'AWS-AWSManagedRulesATPRuleSet',
          statement: {
            managedRuleGroupStatement: {
              name: 'AWSManagedRulesATPRuleSet',
              vendorName: 'AWS',
              managedRuleGroupConfigs: [{
                loginPath: '/loginPath',        
                payloadType: 'JSON',
                usernameField: {
                  identifier: '/form/username', 
                },
                passwordField: {
                  identifier: '/form/password',
                },
              }],
            }
          },
          overrideAction: { none: {} },
          visibilityConfig: {
            cloudWatchMetricsEnabled: true,
            metricName: 'AWS-AWSManagedRulesATPRuleSet',
            sampledRequestsEnabled: true
          }
        },
      ],
    });
  }
}