Azure Local deployment fails at "Validate Active Directory Configuration" (TestClusterAD): some nodes cannot reach a writable DC

Environment

• Azure Local, 4 nodes, ARM Deployment(Custom storage IPs)

Problem

Deployment fails at step "Create the cluster" (0.16.4 - TestClusterAD) with:

"Cluster Validation failed in following tests: Validate Active Directory Configuration - Fail"

The generated cluster validation report says:

• "Connectivity to a writable domain controller from node <Node1> could not be determined because of this error: Could not get domain controller name from machine <Node1>" (same for <Node3>)
• "Node(s) <Node2> <Node4> can reach a writable domain controller"
• Site Name is blank for all four nodes
• All four nodes show the same domain, domain role (Member Server) and OU
• Informational only: missing SPN MSServerClusterMgmtAPI on one node, and the OU does not deny "Delete All Child Objects"

In an earlier run, the same test failed for a different node (<Node4>), retrying worked during validation, but getting this again during deployment.