Instead of using the Update an item action, try updating it through an HTTP request. I rarely ever use the Update item action as this method provides greater control over what gets updated although it is a bit more work to set up. But once you get used to this method, it is rather easy. This example has more fields that need to be updated than I usually need to update in a flow. Note that the FieldName values require the use of the internal name of the field you want to update rather than the display name of the field. Internal names never have a space in them. You can find the internal name by going to the list settings and opening the field in your browser, the internal name is at the end of the URL.
Here is the code for the Uri (replace the highlighted text with the display name of your list): _api/web/lists/getByTitle('Separation Agreements')/items(@{triggerOutputs()?['body/ID']})/validateUpdateListItem
And here is the text of the body, which of course you'll adjust to the fields for your list. The last value, AssignedAttorney, is for updating a people field. Note, this method only works when the people field is restricted to a single person.
{
"formValues": [
{
"FieldName": "ApprovalStatus",
"FieldValue": "Assigned"
},
{
"FieldName": "AttorneyAssigned",
"FieldValue": "@{true}"
},
{
"FieldName": "AttorneyDate",
"FieldValue": "@{formatDateTime(utcNow(), 'MM/dd/yyyy')}"
},
{
"FieldName": "Days",
"FieldValue": "@{div(float(sub(ticks(utcNow()), ticks(triggerOutputs()?['body/Created']))), 864000000000)}"
},
{
"FieldName": "AssignedAttorney",
"FieldValue": "[{'Key':'i:0#.f|membership|@{outputs('Send_email_with_options_Attorney_Assignment')?['body/SelectedOption']}'}]"
}
]
}
This returns the e-mail address of the person I want to populate the people field with: @{outputs('Send_email_with_options_Attorney_Assignment')?['body/SelectedOption']}
