kubernetes secret items not mounted as file path

I have the following yaml:

        volumeMounts:
        - name: app-secret
          mountPath: /app
          readOnly: true
      volumes:
      - name: app-secret
        secret:
          secretName: app-secret
          items:
          - key: app-secret.json
            path: appsettings.secret.json

I expect the secret is mounted on /app/appsettings.secret.json but it isn't. I don't know where it is mounted and the container crashes and I don't have a chance to kubectl exec into the container to inspect where the secret is mounted. My guess is that it wipes out the content of /app. Any advice and insight is appreciated.

This works:

 volumeMounts:
        - name: app-secret
          mountPath: /app/appsettings.secret.json
          subPath: appsettings.secret.json
          readOnly: true
      volumes:
      - name: app-secret
        secret:
          secretName: app-secret
          items:
          - key: app-secret.json
            path: appsettings.secret.json