When creating a capi machineset with invalid ami, the machine will be in Pending status, check awsmachine/machine status, no FailureReason/FailureMessage field. 

4.21.0-0.nightly-2025-10-19-181151

Always

1. Create a capi machineset with invalid ami 
$ cat capi-aws-create-machineset.yaml    
apiVersion: cluster.x-k8s.io/v1beta1
kind: MachineSet
metadata:
  name: aws-machineset3
  namespace: openshift-cluster-api
spec:
  clusterName: ci-ln-x7xfwdt-76ef8-lr7x6
  deletePolicy: Random
  replicas: 1
  selector:
    matchLabels:
      cluster.x-k8s.io/cluster-name: ci-ln-x7xfwdt-76ef8-lr7x6
      machine.openshift.io/cluster-api-cluster: ci-ln-x7xfwdt-76ef8-lr7x6
      machine.openshift.io/cluster-api-machineset: aws-machineset3
  template:
    metadata:
      labels:
        cluster.x-k8s.io/cluster-name: ci-ln-x7xfwdt-76ef8-lr7x6
        machine.openshift.io/cluster-api-cluster: ci-ln-x7xfwdt-76ef8-lr7x6
        machine.openshift.io/cluster-api-machineset: aws-machineset3
    spec:
      bootstrap:
        dataSecretName: worker-user-data
      clusterName: ci-ln-x7xfwdt-76ef8-lr7x6
      infrastructureRef:
        apiVersion: infrastructure.cluster.x-k8s.io/v1beta2
        kind: AWSMachineTemplate
        name: aws-machine-template3
        namespace: openshift-cluster-api
---
apiVersion: infrastructure.cluster.x-k8s.io/v1beta2
kind: AWSMachineTemplate
metadata:
  name: aws-machine-template3
  namespace: openshift-cluster-api
spec:
  template:
    metadata: {}
    spec:
      additionalSecurityGroups:
      - filters:
        - name: tag:Name
          values:
          - ci-ln-x7xfwdt-76ef8-lr7x6-node
      - filters:
        - name: tag:Name
          values:
          - ci-ln-x7xfwdt-76ef8-lr7x6-lb
      additionalTags:
        ci-nat-replace: "false"
        clusterName: ci-ln-gcp98x2-76ef8
        expirationDate: 2025-10-20T08:22+00:00
        kubernetes.io/cluster/ci-ln-x7xfwdt-76ef8-lr7x6: owned
      ami:
        id: ami-0368e7083557a9c5d-invalid
      cloudInit: {}
      iamInstanceProfile: ci-ln-x7xfwdt-76ef8-lr7x6-worker-profile
      ignition:
        storageType: UnencryptedUserData
      instanceMetadataOptions:
        httpEndpoint: enabled
        httpPutResponseHopLimit: 1
        httpTokens: optional
        instanceMetadataTags: disabled
      instanceType: m6a.xlarge-invalid
      rootVolume:
        encrypted: true
        size: 120
        type: gp3
      subnet:
        filters:
        - name: tag:Name
          values:
          - ci-ln-x7xfwdt-76ef8-lr7x6-subnet-private-us-east-1a     
2. Check awsmachine/machine status
3.
    

Machine is stuck in Pending status, no FailureReason/FailureMessage in status.

$ oc get machine.c -n openshift-cluster-api      
NAME                                                CLUSTER                     NODENAME                       PROVIDERID                              PHASE     AGE    VERSION
aws-machineset3-8l4zn                               ci-ln-x7xfwdt-76ef8-lr7x6                                                                          Pending   32m
$ oc get awsmachine -n openshift-cluster-api aws-machineset3-8l4zn -o yaml | grep -A10 status:          
status:
  conditions:
  - lastTransitionTime: "2025-10-21T02:46:48Z"
    message: 0 of 2 completed
    reason: InstanceProvisionFailed
    severity: Error
    status: "False"
    type: Ready
  - lastTransitionTime: "2025-10-21T03:15:31Z"
    message: 'failed to create AWSMachine instance: failed to get root volume from
      image "ami-0368e7083557a9c5d-invalid": operation error EC2: DescribeImages,
      https response error StatusCode: 400, RequestID: 8fe903c0-3a46-4dcf-917b-60ad60d15089,
      api error InvalidAMIID.Malformed: Invalid id: "ami-0368e7083557a9c5d-invalid"'
    reason: InstanceProvisionFailed
    severity: Error
    status: "False"
    type: InstanceReady
  - lastTransitionTime: "2025-10-21T02:46:48Z"
    reason: NotPaused
    status: "False"
    type: Paused
zhsun:aws1/ $ oc get machine.c -n openshift-cluster-api aws-machineset3-8l4zn -o yaml | grep -A10 status:    
status:
  conditions:
  - lastTransitionTime: "2025-10-21T02:46:48Z"
    message: 0 of 2 completed
    reason: InstanceProvisionFailed
    severity: Error
    status: "False"
    type: Ready
  - lastTransitionTime: "2025-10-21T02:46:48Z"
    message: 0 of 2 completed
    reason: InstanceProvisionFailed
    severity: Error
    status: "False"
    type: InfrastructureReady
  - lastTransitionTime: "2025-10-21T02:46:48Z"
    reason: WaitingForNodeRef
    severity: Info
    status: "False"
    type: NodeHealthy
  lastUpdated: "2025-10-21T02:46:48Z"
  observedGeneration: 1
  phase: Pending
  v1beta2:
    conditions:
    - lastTransitionTime: "2025-10-21T02:46:48Z"
      message: ""
      observedGeneration: 1
      reason: NotReady
      status: "False"
      type: Available
    - lastTransitionTime: "2025-10-21T02:46:48Z"
      message: |-
        * InfrastructureReady: 0 of 2 completed
        * NodeHealthy: Waiting for AWSMachine to report spec.providerID
      observedGeneration: 1
      reason: NotReady
      status: "False"
      type: Ready
    - lastTransitionTime: "2025-10-21T02:46:48Z"
      message: ""
      observedGeneration: 1
      reason: DataSecretProvided
      status: "True"
      type: BootstrapConfigReady
    - lastTransitionTime: "2025-10-21T02:46:48Z"
      message: 0 of 2 completed
      observedGeneration: 1
      reason: InstanceProvisionFailed
      status: "False"
      type: InfrastructureReady
    - lastTransitionTime: "2025-10-21T02:46:48Z"
      message: Waiting for AWSMachine to report spec.providerID
      observedGeneration: 1
      reason: InspectionFailed
      status: Unknown
      type: NodeHealthy
    - lastTransitionTime: "2025-10-21T02:46:48Z"
      message: Waiting for AWSMachine to report spec.providerID
      observedGeneration: 1
      reason: InspectionFailed
      status: Unknown
      type: NodeReady
    - lastTransitionTime: "2025-10-21T02:46:48Z"
      message: ""
      observedGeneration: 1
      reason: NotPaused
      status: "False"
      type: Paused
    - lastTransitionTime: "2025-10-21T02:46:48Z"
      message: ""
      observedGeneration: 1
      reason: NotDeleting
      status: "False"
      type: Deleting

Machine is in Failed status with invalid config.