Failed to upgrade 4.15 from 4.16 with vsphere UPI due to 
03-19 05:58:11.372  network                                    4.16.0-0.nightly-2024-03-13-061822   True        False         True       9h      Error while updating infrastructures.config.openshift.io/cluster: failed to apply / update (config.openshift.io/v1, Kind=Infrastructure) /cluster: Infrastructure.config.openshift.io "cluster" is invalid: [spec.platformSpec.vsphere.apiServerInternalIPs: Invalid value: "null": spec.platformSpec.vsphere.apiServerInternalIPs in body must be of type array: "null", spec.platformSpec.vsphere.ingressIPs: Invalid value: "null": spec.platformSpec.vsphere.ingressIPs in body must be of type array: "null", spec.platformSpec.vsphere.machineNetworks: Invalid value: "null": spec.platformSpec.vsphere.machineNetworks in body must be of type array: "null", <nil>: Invalid value: "null": some validation rules were not checked because the object was invalid; correct the existing errors to complete validation]

  upgrade chain 4.11.58-x86_64 - > 4.12.53-x86_64,4.13.37-x86_64,4.14.17-x86_64,4.15.3-x86_64,4.16.0-0.nightly-2024-03-13-061822

    always

    1. Upgrade cluster from 4.15 -> 4.16
    2.
    3.