My apologies that I did not follow the original thread well. Let us try again
Do you have a write-back cache on your devices?But, what we don't understand is why VSAN does not run "as intended" when we turn the whole thing on. The VM disappears, clustering fails and we have to reconnect the whole VSAN over again, sync the targets, revive the storage, etc.. Similar to the issue from the start of the thread.
Full synchronization is expected. It should start when both nodes are online again. HA will be available over iSCSI while full synchronization is running.
Also, make sure the DCs are out of the cluster.
Last but not least. CSVs have their own failover threshold. If they are reachable over iSCSI, it might be necessary to move them between the nodes to bring them online.
Please also note that Microsoft Failover Cluster is a third-party product. All StarWind VSAN does is feed the storage into it. If the storage is available (i.e., one of the partners is synchronized and can be reached over iSCSI (be it over an old session or a new one)), the issue is related to clustering.