Publish Updates Creates Duplicate Deployments Instead of Updating

[udayarayalla-prog]

Hello,

When using "Publish Updates" in NEW Foundry portal for an existing agent, it creates new deployments (v3, v4, v4 duplicate) instead of updating the existing deployment.

I am getting 'Deployment not found' error calling the same agent endpoint after publishing the updates.

"error": {
    "code": "bad_request",
    "message": "Deployment '' not found under Application 'Classification'",
    "param": null,
    "type": "invalid_request_error",
    "details": [],
    "additionalInfo": {
    }
}

}

Expected behavior:

• Publish Updates should update existing deployment
• Traffic should route to latest version automatically
• Old deployments should stop or be replaced

Actual behavior:

• New deployment created each time
• Multiple deployments running simultaneously
• Traffic routing remains on old/empty deployment

Environment:

• Portal: Microsoft Foundry (NEW)
• Project: Foundry project (not hub-based)
• API Version: 2025-11-15-preview
• Agent Type: Managed (Prompt agent)

Workaround:
Creating fresh agents works correctly on first publish. Issue only occurs
on subsequent "Publish Updates" operations.

[leestott]

Hi @udayarayalla-prog

Root cause and status
This is a known issue in the new Microsoft Foundry portal where Publish Updates creates a new agent deployment instead of re‑binding the existing one, but fails to update traffic routing to the latest deployment. As a result, the agent application endpoint points to an empty or missing deployment name, causing the error “Deployment '' not found under Application …”. This typically occurs on the second and subsequent publishes of the same managed (prompt) agent.

Reference: https://learn.microsoft.com/en-us/answers/questions/5659243/azure-ai-error-deployment-not-found

Expected vs actual behavior
•Expected: Publish Updates keeps a stable application endpoint, routes traffic to the latest deployment, and supersedes older deployments.
•Actual: Each publish creates a new running deployment, older deployments remain active, and routing is not updated, leading to failed API calls.

Why the error happens
Publishing creates an Agent Application plus Deployments under it. The stable endpoint should automatically follow the newest deployment, but in this flow the routing target becomes empty or stale after an update, so the service cannot resolve the deployment name.
Reference: https://learn.microsoft.com/en-us/azure/ai-foundry/agents/how-to/publish-agent

Workarounds
•Create a new agent and publish once (works on first publish, but not a long‑term fix).
•Manually manage deployments using the Agent Deployments REST API (explicitly start the intended deployment and stop older ones).
Reference: https://learn.microsoft.com/en-us/rest/api/aifoundry/accountmanagement/agent-deployments?view=rest-aifoundry-accountmanagement-2025-10-01-preview

Scope
•Portal: Microsoft Foundry (new)
•Project type: Foundry project (non hub-based)
•Agent type: Managed / prompt agent
•API version: 2025-11-15-preview

@nicholasdbrady

[nicholasdbrady]

@fosteramanda / @qubitron FYI