How to update a Service Request field from an embedded cx-container?

Summary:

Hi.

On the Service Request create page, I have added a cx-container as a custom section:

It's a pretty simple section wherein I have a text field and a button:

Upon clicking the Add button, I want to populate the Transaction Number value on the Title of the SR. I have created an action chain and I am using the "Set Field Value" action to set the value of the Title, but it isn't working. Any idea what I might be doing wrong?

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