Invalid Expression Error for Field Input Using Dynamic Field Value in PA Flow

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Posted on by PK-18050816-0 Microsoft Employee

Hi Community,

I’m facing an error in my Power Automate cloud flow where an AzureDevops work item creation node is throwing an “invalid expression” error, even when only referencing an input parameter directly from the trigger node (When an agent calls the flow).

Scenario

I have a flow triggered using “When an agent calls the flow” (Copilot Studio / Agent trigger). One of the inputs is:

a Handoff date (Date field type)

I am referencing this field value inside the Create work item action node of Azure DevOps connector, using dynamic content referencing formula- triggerBody()?['date_1'].

The expression is not giving any error message when updating/adding the power fx,

However, the node is throwing the following error upon 'Publish':

“The input parameter(s) of operation 'Create_work_item' contains invalid expression(s). Fix invalid expression(s) for the input parameter(s) of operation 'Create'_work_item'.”

The possibility of the issue being caused by any other expression used in the same node is ruled out, as the flow publishes successfully once this particular field is removed. Additionally, the technical ADO name of the field is also correctly being referred.

what has been tried but didn't work-

changing the field type to 'text' in the trigger node
wrapping the field in coalesce() & other date manipulation formulas
using the expression in a separate 'compose' node

What’s confusing

I am not using any complex expression for this field.
I’m simply referencing the input value from When an agent calls the flow.
Other trigger inputs in the same action are working correctly.
The issue is only happening for the Handoff field.

I am wondering if this is an intrinsic glitch/quirk of powerautomate flow itself, or any logical error. Thank you in advance for any tips, suggestions, or guidance.

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Tomac 4,105 Moderator on at

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Hi @PK-18050816-0

Please copy/paste your screenshots into the comment body section instead of uploading as an attachment. Attachment virus scanning is broken right now and never completes, so we won't be able to see the screenshot.

We'll need to see the action "Create work item" with any expressions used copy/pasted as text so we can evaluate where the issue might be.

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PK-18050816-0 Microsoft Employee on at

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Thanks for answering & bringing that to attention! I have updated the post with the relevant screenshots., including the expression raising the error. Let me know if any other screenshots or info is required.

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Tomac 4,105 Moderator on at

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@PK-18050816-0 Thanks for the follow up.

In a failed flow run, can you copy/paste the output of the trigger so we can see what fields are being delivered to your flow?

Also, have you tried manually typing that expression into the actions instead of copy/pasting it? Sometimes copy/paste from a chatbot will include weird character encoding.

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Haque 3,197 on at

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Hi @PK-18050816-0,

If you suspect date is one of the reasons, then I would suggest avoid Direct Dynamic Content Without Formatting. Means, directly referencing triggerBody()?['date_1'] without formatting can cause errors if the data type or format is incompatible.

Hence, the date input from the agent trigger may be a string, but Azure DevOps expects a date/time value in a specific ISO 8601 format (e.g., yyyy-MM-ddTHH:mm:ssZ). If the input is just a date (without time), you may need to convert or format it explicitly.

In this case, let's use expression to convert or Format Date: Use Power Automate expressions like formatDateTime() to convert the input to the correct format. Example: formatDateTime(triggerBody()?['date_1'], 'yyyy-MM-ddTHH:mm:ssZ'), this ensures the date is in the proper ISO format Azure DevOps expects.

If that is not the case, I will suggest narrow down number of inputs, let's say, you try first with 1(projectName)/2(projectName, courseOwner) fields, if they don't raise any issue increase one by one - ah tedious! But we have to find it out first who is giving trouble!

I am sure some clues I tried to give. If these clues help to resolve the issue brought you by here, please don't forget to check the box Does this answer your question? At the same time, I am pretty sure you have liked the response!

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