I have a very strange effect with a pod on Kubernetes: It tries to mount a volume of type emptyDir, but fails to do so. The events list of the pod brings up the following entries:

LAST SEEN   FIRST SEEN   COUNT     NAME                                                                            KIND      SUBOBJECT   TYPE      REASON        SOURCE                                                    MESSAGE
2m          10h          281       953fb7fe6825ce398f6243fbe2b2df9400d8cbe0-1530827425856-xbg84.153e978b9b811f46   Pod                   Warning   FailedMount   kubelet, ip-172-20-73-118.eu-central-1.compute.internal   Unable to mount volumes for pod "953fb7fe6825ce398f6243fbe2b2df9400d8cbe0-1530827425856-xbg84_example(6cfbf40a-809d-11e8-bb05-0227730cc812)": timeout expired waiting for volumes to attach/mount for pod "example"/"953fb7fe6825ce398f6243fbe2b2df9400d8cbe0-1530827425856-xbg84". list of unattached/unmounted volumes=[workspace]

What's strange is that this works most of the times, but now this has happened. What could be the reason for this? And how to figure out in more detail what went wrong?

Update: As requested in a comment, I have added the pod spec here:

apiVersion: v1
kind: Pod
metadata:
  name: 953fb7fe6825ce398f6243fbe2b2df9400d8cbe0-1530827425856-xbg84
  namespace: example
spec:
  containers:
  - args:
    - --context=/workspace/1b5c4fd2-bb39-4096-b055-52dc99d8da0e
    - --dockerfile=/workspace/1b5c4fd2-bb39-4096-b055-52dc99d8da0e/Dockerfile-broker
    - --destination=registry.example.com:443/example/953fb7fe6825ce398f6243fbe2b2df9400d8cbe0-broker:1530827425856
    image: gcr.io/kaniko-project/executor:732a2864f4c9f55fba71e4afd98f4fdd575479e6
    imagePullPolicy: IfNotPresent
    name: 953fb7fe6825ce398f6243fbe2b2df9400d8cbe0-1530827425856-broker
    volumeMounts:
    - mountPath: /kaniko/.docker/config.json
      name: config-json
      subPath: config.json
    - mountPath: /workspace
      name: workspace
    - mountPath: /var/run/secrets/kubernetes.io/serviceaccount
      name: default-token-mk89h
      readOnly: true
  - args:
    - --context=/workspace/1b5c4fd2-bb39-4096-b055-52dc99d8da0e
    - --dockerfile=/workspace/1b5c4fd2-bb39-4096-b055-52dc99d8da0e/Dockerfile-core
    - --destination=registry.example.com:443/example/953fb7fe6825ce398f6243fbe2b2df9400d8cbe0-core:1530827425856
    image: gcr.io/kaniko-project/executor:732a2864f4c9f55fba71e4afd98f4fdd575479e6
    imagePullPolicy: IfNotPresent
    name: 953fb7fe6825ce398f6243fbe2b2df9400d8cbe0-1530827425856-core
    volumeMounts:
    - mountPath: /kaniko/.docker/config.json
      name: config-json
      subPath: config.json
    - mountPath: /workspace
      name: workspace
    - mountPath: /var/run/secrets/kubernetes.io/serviceaccount
      name: default-token-mk89h
      readOnly: true
  - args:
    - --context=/workspace/1b5c4fd2-bb39-4096-b055-52dc99d8da0e
    - --dockerfile=/workspace/1b5c4fd2-bb39-4096-b055-52dc99d8da0e/Dockerfile-flows
    - --destination=registry.example.com:443/example/953fb7fe6825ce398f6243fbe2b2df9400d8cbe0-flows:1530827425856
    image: gcr.io/kaniko-project/executor:732a2864f4c9f55fba71e4afd98f4fdd575479e6
    imagePullPolicy: IfNotPresent
    name: 953fb7fe6825ce398f6243fbe2b2df9400d8cbe0-1530827425856-flows
    volumeMounts:
    - mountPath: /kaniko/.docker/config.json
      name: config-json
      subPath: config.json
    - mountPath: /workspace
      name: workspace
    - mountPath: /var/run/secrets/kubernetes.io/serviceaccount
      name: default-token-mk89h
      readOnly: true
  initContainers:
  - command:
    - sh
    - -c
    - echo ${CONFIG_JSON} | base64 -d > /config-json/config.json
    env:
    - name: CONFIG_JSON
      value: […]
    image: alpine:3.7
    imagePullPolicy: IfNotPresent
    name: store-config-json
    volumeMounts:
    - mountPath: /config-json
      name: config-json
    - mountPath: /var/run/secrets/kubernetes.io/serviceaccount
      name: default-token-mk89h
      readOnly: true
  restartPolicy: Never
  volumes:
  - emptyDir: {}
    name: config-json
  - name: workspace
    persistentVolumeClaim:
      claimName: example
  - name: default-token-mk89h
    secret:
      defaultMode: 420
      secretName: default-token-mk89h