Azure Resource Manager: Deployment stack stuck in 'Initializing' — Assistance needed to resolve or delete

Problem description

I am facing an issue where a deployment in Azure Resource Manager (ARM) is stuck in a non-terminal 'Initializing' state since August 30, 2026. This prevents further deployments and management operations. I need guidance on how to reset this stack to a terminal state or delete it without affecting the managed resources.

Environment

Service: Azure Resource Manager (ARM); Resource type: deploymentStacks; Region: Sweden Central.

What I've already tried

I checked the stack’s provisioning state using Azure CLI and PowerShell, confirming it remains 'Initializing'. I attempted to delete the stack with detach via CLI and the Azure Portal, but the provisioning state did not change. I also listed and removed deny assignments on the managed resources using CLI and Portal, with no impact (I get the error that "--detach" is unrecognized option, even though I've upgraded my AZ CLI to v2.90). An initial support agent found no activity logs or diagnostic entries related to this deployment stack.

Current status

Currently, the deployment stack remains in the 'Initializing' state and cannot be reset or removed via detach operations. All 24 managed resources are still present and operational. The root cause of this orphaned state is unknown, and further guidance is needed to resolve this issue or safely delete the stack and associated deny assignments to restore resource management.