Azure Functions Flex Consumption Durable Functions Not Executing

Question

Azure Functions Flex Consumption Durable Functions Not Executing

Duncan Hardie 0

We are experiencing an issue with Azure Durable Functions running on Azure Functions Flex Consumption, which has resulted in significant unexpected costs. I am seeking both technical clarification and guidance on billing remediation.

Issue Summary

We deployed Durable Functions orchestrators using:

df.app.orchestration('streamingImportOrchestrator', handler)

The orchestrators:

Register successfully

Appear correctly in the Function App

Can be started using client.startNew()

However, instances remain in a “Pending” state and never execute.

Observed behaviour:

No meaningful orchestration history events

No activity execution

No runtime errors surfaced in the HTTP trigger

Regular HTTP triggers function normally

This indicates that the Function App is operational, but the Durable orchestration is not being dispatched or executed at runtime.

We previously experienced similar behaviour on Flex Consumption earlier this year.

Impact

Because of this:

Jobs were created but never processed

We had to implement fallback logic outside Durable

Orchestration instances and related storage continued incurring charges

Significant engineering time was spent diagnosing platform behaviour

The service was deployed in good faith using a supported Azure configuration. The Durable workflow did not execute as expected, yet billing continued.

Questions

Is Durable Functions fully supported and stable on Flex Consumption for Node-based apps?

Are there known issues with orchestrator dispatch on Flex?

Under these circumstances, what is the correct path to request billing investigation and potential refund/service credit?

I can provide:

Subscription ID

Resource Group

Function App name

Instance IDs

Timestamps

Application Insights logs

Any clarification would be greatly appreciated, as this has had both technical and financial impact.

Thank you.We are experiencing an issue with Azure Durable Functions running on Azure Functions Flex Consumption, which has resulted in significant unexpected costs. I am seeking both technical clarification and guidance on billing remediation.

Issue Summary

We deployed Durable Functions orchestrators using:

df.

The orchestrators:

Register successfully

Appear correctly in the Function App

Can be started using client.startNew()

However, instances remain in a “Pending” state and never execute.

Observed behaviour:

No meaningful orchestration history events

No activity execution

No runtime errors surfaced in the HTTP trigger

Regular HTTP triggers function normally

This indicates that the Function App is operational, but the Durable orchestration is not being dispatched or executed at runtime.

We previously experienced similar behaviour on Flex Consumption earlier this year.

Impact

Because of this:

Jobs were created but never processed

We had to implement fallback logic outside Durable

Orchestration instances and related storage continued incurring charges

Significant engineering time was spent diagnosing platform behaviour

The service was deployed in good faith using a supported Azure configuration. The Durable workflow did not execute as expected, yet billing continued.

Questions

Is Durable Functions fully supported and stable on Flex Consumption for Node-based apps?

Are there known issues with orchestrator dispatch on Flex?

Under these circumstances, what is the correct path to request billing investigation and potential refund/service credit?

I can provide:

Subscription ID

Resource Group

Function App name

Instance IDs

Timestamps

Application Insights logs

Any clarification would be greatly appreciated, as this has had both technical and financial impact.

Thank you.

Pravallika KV 16,945 Reputation points Microsoft External Staff Moderator

2026-03-02T20:24:05.35+00:00
Hi Duncan Hardie,

Thanks for reaching out to Microsoft Q&A.

Enable the Durable Task Scheduler provider:

Follow the “Quickstart: Build a serverless workflow using Durable Functions on Flex Consumption” guide and choose the Durable Task Scheduler storage provider.

In host.json, set your taskHub name explicitly:

{ "extensions": { "durableTask": { "hubName": "MyTaskHub" } } }

Use the Durable Task Scheduler dashboard (preview) to verify that your scheduler is up and that your identity has the Durable Task Data Contributor role.

Check your Application Insights or storage queues for trigger-firing events.

Use the monitoring queries in the “Durable Functions / Monitoring” documentation to confirm if the host is spinning up and dispatching work.

Hope this helps!
Pravallika KV 16,945 Reputation points Microsoft External Staff Moderator

2026-03-06T22:22:30.4733333+00:00

@Duncan Hardie , I have reached out to you over private message. Please check and respond.

1 answer

Your answer

Pravallika KV 16,945 Reputation points Microsoft External Staff Moderator

2026-03-02T20:24:05.35+00:00

Hi Duncan Hardie,

Thanks for reaching out to Microsoft Q&A.

Enable the Durable Task Scheduler provider:

Follow the “Quickstart: Build a serverless workflow using Durable Functions on Flex Consumption” guide and choose the Durable Task Scheduler storage provider.

In host.json, set your taskHub name explicitly:

{ "extensions": { "durableTask": { "hubName": "MyTaskHub" } } }

Use the Durable Task Scheduler dashboard (preview) to verify that your scheduler is up and that your identity has the Durable Task Data Contributor role.

Check your Application Insights or storage queues for trigger-firing events.

Use the monitoring queries in the “Durable Functions / Monitoring” documentation to confirm if the host is spinning up and dispatching work.

Hope this helps!
Pravallika KV 16,945 Reputation points Microsoft External Staff Moderator

2026-03-06T22:22:30.4733333+00:00

@Duncan Hardie , I have reached out to you over private message. Please check and respond.

Answer 1

Hi @Duncan Hardie ,

Check below steps to verify your runtime is actually dispatching work, and how to open a billing support request for the unexpected charges.

Check runtime logs and persistence
- In Application Insights, look for Durable Functions traces (or use the sample Kusto queries in the monitoring docs).
- In your storage account (queues/tables), verify that work items are enqueued by the scheduler and dequeued by the host.
- If you see lots of Pending messages with no dequeue activity, the host isn’t picking up tasks.
Request a billing investigation / credit
- In the Azure portal go to Help + support =>New support request.
- For Issue type, choose Billing =>Charges.
- Provide your Subscription ID, Resource Group, Function App name, affected instance IDs and timestamps.
- The billing team will review your case and can issue a service credit if the platform didn’t behave as documented.

Hope this helps!

References:

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Azure Functions Flex Consumption Durable Functions Not Executing

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