Cache for Redis: Scaling from Standard C1 to C2 — HTTP 409 Conflict / Possible Backend Issue

Problem description

I am attempting to scale my Azure Cache for Redis instance from Standard C1 to C2. However, the operation fails repeatedly with an HTTP 409 Conflict, indicating the resource is busy processing a previous update or under maintenance. Despite this, the cache remains operational, and no resource locks are in place. Also, CLI does not report any update operation taking place. I am seeking guidance on resolving this conflict and successfully scaling the resource.

Environment

Azure Cache for Redis in West Europe, Standard C1 SKU

What I've already tried

I have tried to scale using both Azure Portal and CLI commands, including attempting to scale from Standard C1 to C2. I also verified that no resource locks are present and that the provisioning state is Succeeded. Additionally, I reviewed activity logs and resource state, and I confirmed that the operation path is supported and that the UI indicates supported versions.

Current status

Currently, the cache is operational and serving traffic, but the scale operation remains stuck with repeated HTTP 409 conflicts. I am looking for further troubleshooting steps or guidance to resolve this issue and complete the scale-up process.