In Cross-vCenter NSX and vCenter linked mode environments, ensure that all the secondary NSX Managers are running on the same version as the Primary NSX Manager. It is important to upgrade all the secondary NSX Managers upon upgrading the Primary NSX Manager before upgrading any other NSX components. Do not make any changes, such as create, update, or delete to universal objects until the Primary and all the Secondary NSX Managers are upgraded.
If you are running a mixed version of NSX Managers in a vCenter-linked mode environment, you should receive an error message when you are selecting one or more NSX Managers from the vSphere Web Client. The temporary workaround for this while waiting for the other NSX Manager to upgrade is to create an additional vCenter server user for each vCenter-NSX pair as described in VMware KB 2127061—Upgrading a single NSX Managers in a vCenter-linked mode environment (https://kb.vmware.com/kb/2127061).