It is occured when moving vmk2 from VSS to VDS.

First move the Standby NIC to vDS and then move vmk2 so that the vmk2 does not lose its connection with vCenter.
If the 2NICs are not connected via switch trunk, It cannot connect vmk2 and vCenter, and vmk2 returen to VSS.
Check the switch connection and settings.

==============================================
1.
[vSS(vSwitch0)]
+--active NIC------------------TOR switch A
+--standby NIC-----------------TOR switch B
+--vmk2
+--vCenter

[vDS(VMware HCIA Distributed Switch)]
==============================================
2.
[vSS(vSwitch0)]
+--active NIC------------------TOR switch A
+--
+--vmk2
+--vCenter

[vDS(VMware HCIA Distributed Switch)]
+--standby NIC-----------------TOR switch B
==============================================
3.
[vSS(vSwitch0)]
+--active NIC------------------TOR switch A
+--
+--
+--vCenter

[vDS(VMware HCIA Distributed Switch)]
+--standby NIC-----------------TOR switch B
+--vmk2
==============================================

The other case, it may occure standby vmnic does not move to VDS so VDS has no uplink.
Connect to ESXi via SSH and check the status of vSwitch.

  esxcfg-vswtich -l

If VDS has no uplink, move manually vmnic from VSS to VDS.
Or RASR all nodes and retry initial build.
When retry it, before initial build, check the status of VSS nic failover policy.

  esxcli network vswitch standard policy failover get -v vSwitch0
    Load Balancing: srcport
    Network Failure Detection: link
    Notify Switches: true
    Failback: true
    Active Adapters: vmnic4
    Standby Adapters: vmnic5
    Unused Adapters:

When 2 nics are active, set one nic to standby.

  esxcli network vswitch standard policy failover set -s vmnic5 -v vSwitch

 

Hello;

Is the problem solved? Can you share the latest status?